Engine Cranks But Will Not Start 551t5a

ENGINE CRANKS BUT WILL NOT START Probable Causes • • • • • • • •

Diagnostic codes, event codes, and the power supply for the Electronic Control Module (ECM) Air inlet heater Engine shutdown switches Engine speed/timing Injection actuation pressure Unit injectors Fuel supply Combustion

Recommended Actions Diagnostic Codes, Event Codes, and ECM Power Supply Certain diagnostic codes and/or event codes may prevent the engine from starting. Connect the Caterpillar Electronic Technician (ET) and check for active codes and/or for logged codes. Troubleshoot any codes that are present before continuing with this procedure. Note: If Cat ET will not communicate with the ECM, the problem is most likely with the electrical power supply to the ECM. Refer to Troubleshooting, "Electrical Power Supply Circuit - Test".

Air Inlet Heater Ensure that the air inlet heater is working properly. Ensure that the heater element is in good repair. For additional information on the air inlet heater, refer to Troubleshooting, "Air Inlet Heater Circuit Test".

Engine Shutdown Switches The engine shutdown switches should be in the RUN position. Use Cat ET to the status of the shutdown switches. When a shutdown occurs, the shutdown switch must be reset prior to restarting the engine. On some applications, the keyswitch must be cycled before the ECM will allow engine cranking. Allow the keyswitch power to the ECM to be in the OFF position for at least 15 seconds prior to restarting the engine. Note: If Cat ET will not communicate with the ECM, the problem is most likely with the electrical power supply to the ECM. Refer to Troubleshooting, "Electrical Power Supply Circuit - Test".

Engine Speed/Timing 1. Crank the engine and observe the engine speed on the Cat ET status screen. If Cat ET indicates zero rpm, refer to Troubleshooting, "Engine Speed/Timing Sensor Circuit - Test".

Note: Upon initial cranking, the status for engine speed may indicate that the engine speed signal is abnormal. This message will be replaced with an engine speed once the ECM is able to calculate a speed from the signal. 2. Ensure that the timing reference gear is installed correctly. The engine will not start if the gear was installed backward. Check for proper orientation between the crankshaft and camshaft drive gears. Correct the orientation and/or replace the drive gear, if necessary. Refer to the Disassembly and Assembly for information that relates to the correct installation of the front gear train.

Injection Actuation Pressure 1. Check the engine oil level. Engine oil supplies the injection actuation pressure circuit. The engine oil must be kept at the proper level for fuel injection. 2. If service has recently been performed on the engine, air may be present in the injection actuation pressure circuit. Allow the engine to fully warm up and operate the engine under load in order to purge the air from the injection actuation pressure circuit. 3. Check the injection actuation pressure. Refer to Troubleshooting, "Injection Actuation Pressure - Test" for the correct procedure. 4. Check the operation of the injection actuation pressure control valve. Refer to Troubleshooting, "Injection Actuation Pressure Control Valve Circuit - Test" for the proper troubleshooting procedure.

Injection Actuation Pressure - Test SMCS - 1714-038 System Operation Description: Use the steps that follow to check the operation of the HEUI fuel system. Circle the appropriate answer in the "Results" section of each test step. Complete all of the test steps that are in this procedure. Return the pages of this procedure with any of the requested parts through Caterpillar's return system.

Left side engine view (typical component locations) (1) Injection Actuation Pressure Control Valve (IAPCV) (2) Injection actuation pressure sensor (3) J2/P2 ECM connector (4) Fuel injection pump outlet port (5) Line for low pressure oil

Test Step 1. Symptoms The following symptoms may occur if there is a problem with the HEUI fuel system: • The engine cranks but the engine will not start. The engine runs rough. • The engine is erratic or unstable at idle or running. • Low power The following diagnostic codes might be currently active or logged: • 164-00 High Injectuation Actuation Pressure • 164-02 Injectuation Actuation Pressure signal irratic • 164-11 Injectuation Actuation Pressure system fault A. Connect the Caterpillar Electronic Technician (ET) to the service tool connector. •

B. Restore the electrical power to the ECM. DO NOT START THE ENGINE. C. Print the "Lifetime Totals" and the "Configuration" screen. D. Check for active diagnostic codes. Expected Result: There are no active diagnostic codes with the electrical power to the ECM restored while the engine is off. Results: • OK - None of these codes are active with the electrical power to the ECM restored while the engine is off. Proceed to Test Step 2. • Not OK - 164-03 or 164-04 is active with the electrical power to the ECM restored while the engine is off. Repair: Refer to Troubleshooting, "Analog Sensor Open or Short Circuit - Test". •

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STOP Not OK - A 164-02 diagnostic code is active with the electrical power to the ECM restored while the engine is off. Repair: Refer to Troubleshooting, "Injection Actuation Pressure Sensor - Test". STOP Not OK - 164-00 or 164-11 is active with the electrical power to the ECM restored while the engine is off. Repair: your Engine Technical Communicator (TC).

STOP Test Step 2. Check the Engine Oil Level A. Check the engine oil level. Refer to Operation and Maintenance Manual, "Engine Oil Level Check". B. If the engine oil level is low add oil to the engine. C. Try to start the engine. Expected Result: The engine has started. Results: • OK - The engine starts. Proceed to Test Step 9. • Not OK - The engine does not start. Proceed to Test Step 3. Test Step 3. Crank the Engine and Record the Engine Data From Cat ET Your answer indicated that the engine oil level is satisfactory. A. Crank the engine and observe the "Injection Actuation Pressure" and "Engine RPM". ________ Record the actual injection actuation pressure. ________ Record the engine speed. Expected Result:

The injection actuation pressure is above 6 MPa (870 psi). Results: • OK - The injection actuation pressure is above 6 MPa (870 psi). Repair: The HEUI system is functioning correctly. Refer to Troubleshooting, "Engine Cranks but Will Not Start" which is located in the "Troubleshooting without a Diagnostic Code" section. •

STOP Not OK - The injection actuation pressure is below 6 MPa (870 psi). Proceed to Test Step 4.

Test Step 4. Check the Oil Pressure at the Fuel Injection Pump Outlet Port Locate the high pressure oil line that supplies high pressure oil to the cylinder head. Remove the oil line and install the 8T-0852 Pressure Gauge to the line or to the high pressure port at the pump. Crank the engine and record the oil pressure that is indicated on the gauge. Note: The pressure readings may vary between gauges. ________ Observed pressure reading ________ Observed RPM ________ Observed "Injection Actuation Output Percent" Expected Result: The oil pressure is above 27.5 MPa (4000 psi). Results: • OK - The oil pressure is above 27.5 MPa (4000 psi). Repair: Remove the pressure gauge from the engine. Proceed to Test Step 8. • Not OK - The oil pressure is below 27.5 MPa (4000 psi). Proceed to Test Step 5. Test Step 5. Install a Test Plug and Recheck the Oil Pressure A. Remove the Injection Actuation Pressure Control Valve (IAPCV). B. Install a 219-2368 Plug (DIAGNOSTIC) and 9X-1484 Seal Kit and perform the pressure test at the fuel injection pump outlet port. Crank the engine and record the results. ________ Observed pressure reading Note: If the 219-2368 Plug (DIAGNOSTIC) is not available, proceed to "Install a New IAPCV and Check the Oil Pressure". Expected Result: The oil pressure is above 27.5 MPa (4000 psi). Results: • OK - The oil pressure is above 27.5 MPa (4000 psi). Repair: The HEUI pump is OK. Replace the IAPCV and recheck the oil pressure. If the problem continues technical . STOP

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Not OK - The oil pressure is below 27.5 MPa (4000 psi). Remove the pressure gauge from the engine. Proceed to Test Step 7.

Test Step 6. Install a New IAPCV and Check the Oil Pressure Note: Use this Test Step only if the 219-2368 Plug (DIAGNOSTIC) is not available. A. Install a new IAPCV onto the high pressure oil pump. Refer to Disassembly and Assembly, "Injection Actuation Pressure Control Valve - Remove and Install". B. Check the oil pressure at the fuel injection pump outlet port. Record the pressure reading. ________ Observed pressure reading Expected Result: The oil pressure measures above 27.5 MPa (4000 psi). Results: • OK - The oil pressure is above 27.5 MPa (4000 psi). Repair: The replacement of the IAPCV has corrected the problem. Remove the test equipment from the engine. that the repair has resolved the problem. •

STOP Not OK - The oil pressure is below 27.5 MPa (4000 psi). Remove the new IAPCV and reinstall the original IAPCV. Proceed to Test Step 7.

Test Step 7. Check the Fuel Injection Pump Drive Gear A. Remove the high pressure oil pump. Refer to Disassembly and Assembly, "Unit Injector Hydraulic Pump - Remove". B. Check for any physical damage to the drive gear. C. that the drive gear and the retaining bolt are properly tightened. Also that the pump shaft rotates freely. Expected Result: The drive gear and the retaining bolt for the high pressure oil pump are tight. The pump shaft rotates freely. Results: • OK - The drive gear bolt is properly tightened and the pump shaft rotates freely. Repair: Replace the high pressure oil pump. Refer to Disassembly and Assembly, "Unit Injector Hydraulic Pump - Install". that the repair has resolved the problem. If this does not fix the problem, technical . •

STOP Not OK - The pump shaft does not rotate freely. Repair: Replace the high pressure oil pump. Refer to Disassembly and Assembly, "Unit Injector Hydraulic Pump - Install". that the repair has resolved the problem. If this does not fix the problem, technical . STOP

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Not OK - The drive gear bolt is loose. The pump shaft rotates freely and there is no obvious mechanical damage that would indicate a different problem. Repair: Replace the drive gear, if necessary. Tighten the drive gear bolt. Refer to Specifications, "Unit Injector Hydraulic Pump". Reinstall the pump. Refer to Disassembly and Assembly, "Unit Injector Hydraulic Pump - Install". Recheck the pressure in order to ensure that the problem has been resolved.If this does not fix the problem, replace the high pressure oil pump. that the repair has resolved the problem.

STOP Test Step 8. Check the High Pressure Oil System for Leaks A. Remove the valve cover and inspect the high pressure oil system for oil leaks. a. While the engine is being cranked, inspect the area around the injector bores for any signs of oil leakage. b. Inspect the spill ports of the injector for excessive oil. All six injectors should spill the same amount of oil. Expected Result: No leaks are apparent. Results: • OK - The high pressure oil system is not leaking. Repair: Call technical for assistance. •

STOP Not OK - A leak in the high pressure oil system has been found. Repair: Replace the O-ring on the injector or replace the damaged injector. that the repair has resolved the problem.

STOP Test Step 9. Operate the Engine and Check for Diagnostic Codes A. Restore the electrical power to the (engine) ECM. Start the engine. B. While the engine is running, use Cat ET to check for the following diagnostic codes: • 164-00 • 164-02 164-11 Place a check beside the codes that are active or logged. • ________ 164-00 • ________ 164-02 • ________ 164-11 Stop the engine. •

Expected Result: None of the diagnostic codes are active.

Results: • OK - None of the diagnostic codes that are mentioned above are active. Proceed to Test Step 10. • Not OK - Either a 164-00 or a 164-11 is active. A 164-02 may also be active at this time. Proceed to Test Step 10. •

Not OK - 164-02 is active, but 164-00 and 164-11 are not active at this time. Repair: Refer to Troubleshooting, "Injection Actuation Pressure Sensor - Test".

STOP Test Step 10. Evaluate the Quality of the Oil Extended oil drain intervals may affect the operation of the HEUI high pressure oil system. Refer to the Operation and Maintenance Manual, "Engine Oil" for additional information concerning proper oil change intervals. A. Check the maintenance records for the engine. Ensure that the customer has not exceeded the suggested oil change interval. Expected Result: The customer has not exceeded the suggested oil change interval and an oil change does not need to be performed. Results: • OK - The engine has been properly maintained. Proceed to Test Step 11. • Not OK - The customer has exceeded the suggested oil change interval for the engine. Repair: Perform an oil change on the engine. Refer to Operation and Maintenance Manual, "Engine Oil and Filter - Change".Run the engine throughout the operating rpm range for 10 to 15 minutes. This will purge any trapped air or debris that is in the system. If the problem still exists or if the problem recurs in a short period or time, proceed to Test Step 11. Test Step 11. Perform the "Injection Actuation Pressure Test" A. Install 8T-0852 Pressure Gauge on the high pressure oil rail. B. Connect Cat ET to the service tool connector. C. Perform the "Injection Actuation Pressure Test" in the using Cat ET. Record the results in Table 1. Note: The "Injection Actuation Pressure Test" can be used to vary the injection actuation pressure. The test adjusts the oil pressure in steps. Some versions of Cat ET may have three steps in the test and some versions of Cat ET may have four steps in the test. Table 1 Step

Manual pressure gauge

Cat ET

Difference

1 2 3 4 Expected Result: The pressure that is measured with the pressure gauge for each step and the pressure that is displayed on Cat ET for each step are within 1379 kPa (200 psi). Results: • OK - The pressure difference is within specifications. The injection actuation pressure sensor is operating properly. Proceed to Test Step 12. • Not OK - The pressure difference is not within specifications. Repair: The injection actuation pressure sensor may be faulty. Replace the sensor and repeat this test step. If the problem still exists, reinstall the original sensor and proceed to Test Step 12. Test Step 12. Perform the "Injection Actuation Pressure Test" at both Low Idle and at High Idle Start the engine. Perform the "Injection Actuation Pressure Test" at low idle and at high idle. Record the results in Table 2. Table 2 Low Idle Step

Actual injection pressure from Cat ET

"Injection Pressure Percentage Output" from Cat ET

1 2 3 4 High Idle Step

Actual injection pressure from Cat ET

"Injection Pressure Percentage Output" from Cat ET

1 2 3 4 Expected Result: The "Injection Actuation Pressure Output" is between 0 percent and 65 percent. Results: • OK - The "Injection Actuation Pressure Output" is within specifications. Repair: Call technical for assistance. •

STOP Not OK - The "Injection Actuation Pressure Output" is not within specifications. Proceed to Test Step 13.

Test Step 13. Install a New IAPCV and Retest the System Install a new IAPCV and perform the "Injection Actuation Pressure Test" at low idle and at high idle. Record the results in Table 3. Table 3 Low Idle Step

Actual injection pressure from Cat ET

"Injection Pressure Percentage Output" from Cat ET

1 2 3 4 High Idle Step

1 2

Actual injection pressure from Cat ET

"Injection Pressure Percentage Output" from Cat ET

3 4 Expected Result: The "Injection Actuation Pressure Output" is between 0 percent and 65 percent. Results: • OK - The "Injection Actuation Pressure Output" is within specifications. Repair: The replacement of the IAPCV corrected the problem. Run the engine under normal operating conditions in order to that the original problem has been resolved. •

STOP Not OK - The "Injection Actuation Pressure Output" is not within specifications. Reinstall the original IAPCV. Proceed to Test Step 14.

Test Step 14. Remove the IAPCV and Check the Oil Pressure A. Remove the IAPCV. Refer to Disassembly and Assembly, "Injection Actuation Pressure Control Valve - Remove and Install". B. Replace the IAPCV with a 219-2368 Plug (DIAGNOSTIC) and 9X-1484 Seal Kit . C. Locate the high pressure oil line that supplies high pressure oil to the cylinder head. Remove the oil line and install the 8T-0852 Pressure Gauge to the line or to the high pressure port at the pump. Crank the engine and record the oil pressure that is indicated on the gauge. Note: The pressure readings may vary between gauges. ________ Observed pressure reading ________ Observed RPM Expected Result: The oil pressure is above 27.5 MPa (4000 psi). Results: • OK - The oil pressure is above 27.5 MPa (4000 psi). The high pressure oil pump is operating correctly. Proceed to Test Step 16. •

Not OK - The oil pressure is below 27.5 MPa (4000 psi). Repair: The high pressure oil pump may be faulty. Remove the pressure gauge from the engine. Proceed to Test Step 15.

Test Step 15. Check the Fuel Injection Pump Drive Gear A. Remove the high pressure oil pump. Refer to Disassembly and Assembly, "Unit Injector Hydraulic Pump - Remove". B. Check for any physical damage to the drive gear.

C. that the drive gear and the retaining bolt are properly tightened. Also that the pump shaft rotates freely. Expected Result: The drive gear and the retaining bolt for the high pressure oil pump are tight. The pump shaft rotates freely. Results: • OK - The drive gear bolt is properly tightened and the pump shaft rotates freely. Repair: Replace the high pressure oil pump. Refer to Disassembly and Assembly, "Unit Injector Hydraulic Pump - Install". that the repair resolved the problem.If this does not fix the problem, technical . •

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STOP Not OK - The pump shaft does not rotate freely. Repair: Replace the high pressure oil pump. Refer to Disassembly and Assembly, "Unit Injector Hydraulic Pump - Install". that the repair resolved the problem.If this does not fix the problem, technical . STOP Not OK - The drive gear bolt is loose. The pump shaft rotates freely and there is no obvious mechanical damage that would indicate a different problem. Repair: Replace the drive gear, if necessary. Tighten the drive gear bolt. Refer to Specifications, "Unit Injector Hydraulic Pump". Reinstall the pump. Refer to Disassembly and Assembly, "Unit Injector Hydraulic Pump - Install". Check the pressure in order to ensure that the problem has been resolved.If this does not fix the problem, replace the high pressure oil pump. that the repair has resolved the problem.

STOP Test Step 16. Check the High Pressure Oil System for Leaks A. Remove the valve cover and inspect the high pressure oil system for oil leaks. a. While the engine is being cranked, inspect the area around the injector bores for any signs of oil leakage. b. Inspect the spill ports of the injector for excessive oil. All six injectors should spill the same amount of oil. Expected Result: No leaks are apparent. Results: • OK - The high pressure oil system does not appear to be leaking. Repair: Call technical for assistance. •

STOP Not OK - A leak has been detected in the high pressure oil system.

Repair: Replace the O-ring on the injector or replace the damaged injector. that the repair has resolved the problem. STOP

Unit Injectors Perform the "Injector Solenoid Test" on Cat ET in order to determine if each of the injector solenoids are being energized by the ECM. Refer to Troubleshooting, "Injector Solenoid Circuit - Test" for additional information.

Fuel Supply 1. Visually check the fuel level in the fuel tank. Do not rely on the fuel gauge only. If necessary, add fuel to the fuel tank. If the engine has been run out of fuel, it will be necessary to purge the air from the fuel system. Refer to Operation and Maintenance Manual, "Fuel System Prime" for the correct procedure. 2. Check the fuel lines for the following problems: restrictions, collapsed lines and pinched lines. If problems are found with the fuel lines, repair the lines and/or replace the lines. 3. Check the fuel tank for debris or foreign objects which may block the fuel supply.

NOTICE Do not crank the engine continuously for more than 30 seconds. Allow the starting motor to cool for two minutes before cranking the engine again. 4. Prime the fuel system if any of the following procedures have been performed: o Replacement of the fuel filters o Service on the low pressure fuel supply circuit o Replacement of unit injectors Note: A sight glass in the low pressure supply line is helpful in diagnosing air in the fuel. Refer to Testing and Adjusting for more information. 5. Check fuel quality. Cold weather adversely affects the characteristics of the fuel. Refer to the applicable Operation and Maintenance Manual for information on improving the characteristics of the fuel during cold weather operation. 6. Check the filtered fuel pressure while the engine is being cranked. Refer to Testing and Adjusting for the correct pressure values. If the fuel pressure is low, replace the fuel filters. If the fuel pressure is still low, check the following items: fuel transfer pump, fuel transfer pump

coupling and fuel pressure regulating valve. Refer to Testing and Adjusting for more information.

Combustion Check for combustion problems.

Air Inlet Heater Circuit - Test System Operation Description: Use this procedure to troubleshoot any suspect problems with the air inlet heater circuit. This procedure covers the following diagnostic codes: • 617-05 Air Inlet Heater Relay open/current below normal • 617-06 Air Inlet Heater Relay grounded/current above norm The air inlet heater improves the engine's ability to start when the engine is cold. The air inlet heater also reduces white smoke when the engine is cold. The Electronic Control Module (ECM) controls the operation of the air inlet heater via the air inlet heater relay. The operation of the air inlet heater is determined by the following cycles: Power Up Cycle - The air inlet heater is turned on for two seconds after the ECM is first powered up. This will happen regardless of temperatures and engine speed. Preheat Cycle - If the "SUM" of the coolant temperature and the inlet manifold air temperature is less than 25 °C (109 °F), then the heater will remain on up to 30 seconds. If the engine speed is zero after 30 seconds, the heater is turned off regardless of the temperature. Crank Cycle - If the "SUM" of the coolant temperature and the inlet manifold air temperature is still less than 25 °C (109 °F), the air inlet heater will remain on while the engine is being cranked. Running Cycle - If the "SUM" of the coolant temperature and the inlet manifold air temperature is less than 35 °C (127 °F), then the air inlet heater will remain on for seven minutes. Postheat Cycle - The air inlet heater is cycled on and off for an additional 13 minutes if the "SUM" of the coolant temperature and the inlet manifold air temperature is still less than 35 °C (127 °F). The air inlet heater will turn on for ten seconds and the air inlet heater will turn off for ten seconds. Note: When you convert the "SUM" of two temperatures that are in degrees Celsius, the resulting value in degrees Fahrenheit will be incorrect. The two temperatures must be converted prior to the addition of the two values. • Convert the reading for the coolant temperature from degrees Celsius to degrees Fahrenheit. • Convert the reading for the inlet manifold air temperature from degrees Celsius to degrees Fahrenheit.

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Add the two conversions together in order to arrive at the correct conversion for the sum in degrees Fahrenheit. Refer to the example that is in Table 1. Table 1 Example Reading

°C

°F

Coolant Temperature

15 °C

59 °F

Inlet Manifold Air Temperature

10 °C

50 °F

"SUM" (1)

25 °C

109 °F

(1)

The sum cannot be directly converted. The direct conversion of 25 °C is 77 °F.

Schematic of the circuit for the air inlet heater

Test Step 1. Inspect Electrical Connectors and Wiring A. Remove power from the ECM. B.

Left side engine view (1) Air inlet heater relay (2) Connector for the air inlet heater relay (3) Air inlet heater (4) J2/P2 ECM connectors

B. Thoroughly inspect all connections for components (1) and (3). Also, thoroughly inspect connectors (2) and (4). Refer to Troubleshooting, "Electrical Connectors - Inspect" for details.

(P2-9) Air inlet heater −

(P2-12) Air inlet heater +

C. Perform a 45 N (10 lb) pull test on each of the wires in the ECM connector that are associated with the air inlet heater. D. Check the allen head screw at each ECM connector for the proper torque. Refer to Troubleshooting, "Electrical Connectors - Inspect" for the correct torque values. E. Check the harness and wiring for abrasion and for pinch points from the air inlet heater back to the ECM and from the air inlet heater back to the battery. Expected Result: All connectors, pins and sockets are completely coupled and/or inserted and the harness and wiring are free of corrosion, of abrasion and of pinch points.

Results: • OK - The harness and connectors appear to be OK. Proceed to Test Step 2. • Not OK - A problem has been found with a connector and/or wiring. Repair: Repair the connectors or wiring and/or replace the connectors or wiring. Ensure that all of the seals are properly in place and ensure that the connectors are completely coupled. that the repair eliminates the problem. STOP Test Step 2. Check for Active Diagnostic Codes A. Connect Caterpillar Electronic Technician (ET) to the service tool connector. B. Restore power to the ECM. C. Start the "Air Inlet Heater Override" on Cat ET and observe the test lamp. Note: Do not leave the "Air Inlet Heater Override" ON. Avoid unnecessary cycling of the air inlet heater in order to prevent the battery from discharging. The "Air Inlet Heater Override" has a one minute timer that disables the test when the time expires. D. Stop the "Air Inlet Heater Override". E. Remove power from the ECM. Expected Result: One of the following diagnostic codes is active: • •

617-05 617-06

Results: • 617-05 is Active - The ECM detects an open circuit between the air inlet heater relay and the ECM. Proceed to Test Step 3. • 617-06 is Active - The ECM detects a short circuit between the air inlet heater relay and the ECM. Proceed to Test Step 4. • No Codes are Active - There are no active diagnostic codes for the air inlet heater relay. Proceed to Test Step 6. Test Step 3. Check for an Open Circuit in the Air Inlet Heater Relay's Control Circuit

Small terminals for the air inlet heater relay's control circuit (typical example)

A. B. C. D.

Disconnect the wires from the small terminals for the air inlet heater relay's control circuit. Install a test lamp across the wires. Restore power to the ECM. Start the "Air Inlet Heater Override" on Cat ET and observe the test lamp. Note: The "Air Inlet Heater Override" has a one minute timer in order to disable the test when the time expires. E. Stop the "Air Inlet Heater Override". F. Remove power from the ECM. Expected Result: The test lamp illuminated while the override was active. Results: • OK - The test lamp illuminated while the override was active. The open circuit is in the relay. Repair: Replace the air inlet heater relay. Clear any diagnostic codes. that the problem is resolved. •

STOP Not OK - The test lamp did not illuminate while the override was active. Leave the wires disconnected from the small terminals of the relay. Proceed to Test Step 5.

Test Step 4. Check for a Short Circuit to the Coil of the Air Inlet Heater Relay

Small terminals for the air inlet heater relay's control circuit (typical example)

A. Disconnect the wires from the small terminals for the air inlet heater relay's control circuit. B. Restore power to the ECM. C. Start the "Air Inlet Heater Override" on Cat ET. Note: The "Air Inlet Heater Override" has a one minute timer in order to disable the test when the time expires. D. Stop the "Air Inlet Heater Override". E. Remove power from the ECM. Expected Result: The short circuit diagnostic code 06 changed to an open circuit diagnostic code 05 when the control wires to the air inlet heater relay were disconnected.

Results: • OK - The short circuit diagnostic code changed to an open circuit diagnostic code. Repair: There is a short circuit in the air inlet heater relay. Replace the air inlet heater relay and clear the diagnostic codes. that the repair eliminates the problem. •

STOP Not OK - The short circuit diagnostic code did not change. Proceed to Test Step 5.

Test Step 5. Check the Operation of the ECM by Creating an Open and Short at the ECM Connector A. Check the operation of the ECM by creating an open at the ECM. a. Remove power from the ECM. b. Disconnect the P2 ECM connector. Thoroughly inspect both halves of the connector for signs of corrosion and/or for moisture. c. Remove the wires for the air inlet heater relay from the P2 ECM connector. Install wire jumpers with Deutsch sockets into the sockets for the air inlet heater relay. Ensure that the wire jumpers are not touching any other wires. Reconnect the P2 connector. d. Restore power to the ECM. e. Start the "Air Inlet Heater Override" on Cat ET. Note: The "Air Inlet Heater Override" has a one minute timer in order to disable the test when the time expires. A 05 diagnostic code should be active for the air inlet heater relay. f. Remove power from the ECM. B. Check the operation of the ECM by creating a short at the ECM. a. Install a jumper wire between the two wire jumpers for the air inlet heater relay that were installed in the previous step. b. Restore power to the ECM. c. Start the "Air Inlet Heater Override" on Cat ET. Note: The "Air Inlet Heater Override" has a one minute timer in order to disable the test when the time expires. A 06 diagnostic code should be active for the air inlet heater relay. d. Remove power from the ECM. e. Remove the wire jumpers and reconnect ECM connector J2/P2. Expected Result: An open circuit diagnostic code 05 is active when the wires for the air inlet heater relay are removed from the ECM connector. A short circuit diagnostic code 06 is active when the jumper wire is installed across the wires for the air inlet heater relay. Results:

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OK - The ECM is working properly. The problem is in the wiring between the ECM and the air inlet heater relay. Repair: Repair the wires and/or the connector. STOP Not OK - One of the following conditions exists: The open circuit diagnostic code 05 is not active when the harness is disconnected. The short circuit diagnostic code 06 is not active when the jumper wire is installed. Repair: Perform the following repair: 1. Temporarily connect a spare ECM. 2. Remove all jumper wires and reconnect all connectors and wires. 3. Recheck the system for active diagnostic codes. 4. Repeat this test step. 5. If the problem is resolved with the spare ECM, reconnect the suspect ECM. 6. If the problem returns with the suspect ECM, replace the ECM. 7. that the repair eliminates the problem.

STOP Test Step 6. Check for Battery Voltage to the Air Inlet Heater Relay A. Remove the wire from the +Battery side of the air inlet heater relay. B. Connect a test lamp between the wire from the +Battery side of the air inlet heater relay and engine ground. C. Restore power to the ECM. D. Observe the test lamp. E. Remove power from the ECM. Expected Result: The test lamp illuminated. Results: • OK - The test lamp illuminated. Battery voltage is reaching the air inlet heater relay. Proceed to Test Step 7. • Not OK - The test lamp did not illuminate. Repair: Battery voltage is not reaching the relay. Ensure that the circuit breaker is not tripped. Repair the harness from the battery to the air inlet heater relay. that the repair eliminates the problem. STOP Test Step 7. Check for Voltage Output at the Air Inlet Heater Relay A. Reconnect the wire from the +Battery to the air inlet heater relay. B. Remove the wire to the air inlet heater from the air inlet heater relay.

C. Connect a test lamp between the output terminal of the air inlet heater relay and engine ground. D. Restore power to the ECM. E. Observe the test lamp. The test lamp should not be illuminated, since the air inlet heater relay is not energized. If the test lamp is illuminated, ensure that the test lamp is connected to the output side of the air inlet heater relay. F. Run the "Air Inlet Heater Override" on Cat ET and observe the test lamp. Note: The "Air Inlet Heater Override" has a one minute timer in order to disable the test when the time expires. G. Stop the "Air Inlet Heater Override". H. Remove power from the ECM. Expected Result: The test lamp illuminated while the override was active. Results: • OK - The test lamp illuminated while the override was active. The air inlet heater relay and the +Battery connection to the air inlet heater relay are operating correctly. Proceed to Test Step 8. • Not OK - The test lamp did not illuminate while the override was active. Repair: Replace the air inlet heater relay. that the repair eliminates the problem. STOP Test Step 8. Check the Wiring Between the Air Inlet Heater Relay and the Air Inlet Heater A. Reconnect the wire from the air inlet heater relay to the air inlet heater. B. Disconnect the wire between the air inlet heater relay and the air inlet heater from the air inlet heater. C. Connect a test lamp between the wire at the air inlet heater and engine ground. D. Restore power to the ECM. E. Run the "Air Inlet Heater Override" on Cat ET and observe the test lamp. Note: The "Air Inlet Heater Override" has a one minute timer in order to disable the test when the time expires. F. Stop the "Air Inlet Heater Override". G. Remove power from the ECM. H. Reconnect the wire between the air inlet heater relay and the air inlet heater. Expected Result: The test lamp illuminated while the override was active. Results: • OK - The test lamp illuminated while the override was active. The wire from the air inlet heater relay to the air inlet heater is OK. Proceed to Test Step 9.

•

Not OK - The test lamp did not illuminate while the override was active. Repair: There is an open in the wire between the air inlet heater relay and the air inlet heater. Replace the wire. that the repair eliminates the problem.

STOP Test Step 9. Measure the Current through the Air Inlet Heater A. Connect a 155-5176 AC/DC Current Probe or an equivalent inductive pickup clamp around wire between the air inlet heater relay and the air inlet heater. B. Connect the current probe to a multimeter. C. Restore power to the ECM. D. Run the "Air Inlet Heater Override" on Cat ET and observe the current reading on the multimeter. Note: Do not leave the "Air Inlet Heater Override" On. Avoid unnecessary cycling of the air inlet heater in order to prevent the battery from discharging. The "Air Inlet Heater Override" has a one minute timer in order to disable the test when the time expires. E. Stop the "Air Inlet Heater Override". F. Remove power from the ECM. Expected Result: The current reading is between 77 and 95 Amperes. Results: • OK - The current is within the specified ranges. Repair: The current is within the specified ranges. The air inlet heater circuit appears to be operating correctly at this time. If an intermittent problem is suspected, refer to Troubleshooting, "Electrical Connectors - Inspect". •

STOP Not OK - The current reading is not within the specified ranges. Repair: Check continuity of the wire between the air inlet heater and engine ground. Check the connections at the air inlet heater and at engine ground for corrosion. If the wire between the air inlet heater and engine ground is OK, replace the air inlet heater. that the problem is resolved. STOP

Engine Speed/Timing Sensor Circuit - Test SMCS - 1912-038 System Operation Description:

Use this procedure to troubleshoot any suspect problems with the following sensors: • Primary engine speed/timing sensor • Secondary engine speed/timing sensor This procedure covers the following diagnostic codes: 190-02 Loss of Engine Speed Signal • 190-11 Engine Speed Sensor mechanical failure • 342-02 Loss of Secondary Engine Speed signal • 342-11 Secondary Engine Speed Sensor mechanical failure The engine uses two engine speed/timing sensors. The primary engine speed/timing sensor and the secondary engine speed/timing sensor are used to detect the reference for engine speed and for engine timing from a unique pattern in the timing reference ring. The timing reference ring is located on the back of the camshaft gear. To determine rpm, the Electronic Control Module (ECM) counts the time between pulses that is created by the sensor as the gear rotates. Under normal operation, the secondary engine speed/timing sensor is used to determine timing for starting purposes. The secondary engine speed/timing sensor is used to determine when the piston in the No. 1 cylinder is at the top of the compression stroke. When the timing has been established, the primary engine speed/timing sensor is then used to monitor engine speed. When the timing has been established, the ECM triggers each injector in the correct firing order at the correct time. The actual timing and duration of each injection is based on engine rpm and on load. If the engine is running and the signal from one sensor is lost, no change in engine performance will be noticed. If the engine is running and the signals from both sensors are lost, fuel injection will be terminated and the engine will be shut down by the ECM. The engine will start when only one sensor signal is present. The engine will not start if the signals from both sensors are lost. Both sensors are magnetic sensors. The two sensors are not interchangeable. If a replacement of the ECM is required, the ECM parameters and the timing calibration can be transferred from the suspect ECM to the replacement ECM. This feature requires the Caterpillar Electronic Technician (ET) and this feature is only possible if the existing ECM can communicate with Cat ET. Use the "Copy Configuration - ECM Replacement" feature on Cat ET. •

Complete all of the following tasks when you install a speed/timing sensor: • Ensure that an O-ring is installed on the sensor. If the O-ring is damaged or missing, replace the O-ring. • Lubricate the O-ring with oil. • Ensure that the sensor is fully seated into the engine before tightening the bracket bolt. • Ensure that the electrical connector is latched. • Ensure that the harness is properly secured, and ensure that each tie-wrap is placed in the correct location.

Illustration 1

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Schematic for the engine speed/timing sensors

Test Step 1. Check for Diagnostic Codes A. Connect Cat ET to the service tool connector. Refer to Troubleshooting, "Electronic Service Tools". B. Restore electrical power to the engine ECM. C. Start the engine and run the engine until the engine is at the normal operating temperature. Note: If the engine will not start, monitor the engine rpm on Cat ET while the engine is being cranked. Cat ET may need to be powered from another battery while the engine is being cranked. D. Wait at least 30 seconds for activation of the diagnostic codes. Look for these codes on Cat ET: o 190-02 o 190-11 o 342-02 o 342-11 Expected Result: One or both of the diagnostic codes that are listed above are logged or active. Note: If the engine will not start and Cat ET displayed 0 rpm during cranking, select "No Engine rpm". Results: • No Engine rpm - Engine rpm is not indicated on Cat ET. Proceed to Test Step 2. • Active or logged code - There is an active diagnostic code or a logged diagnostic code for an engine speed/timing sensor. Proceed to Test Step 4.

•

No codes - Neither code is active or logged. Repair: Refer to the appropriate symptoms in Troubleshooting, "Troubleshooting Without a Diagnostic Code".

STOP Test Step 2. Check the Installation of the Sensor Assembly A. Remove electrical power from the engine ECM. B.

Illustration 2

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Left side view (1) Engine (2) Mounting flange (3) Bracket

B. Visually inspect the sensor assembly without removing the sensor assembly from the engine. Flanges (2) must be flush against engine (1) in order to ensure proper operation. Inspect bracket (3). that the bracket securely holds the flanges of the sensors flush against the engine. that the bracket is not bent. If the bracket is bent or if an obstruction is preventing the sensor assembly from being installed correctly, the engine will not start. Note: The bracket cannot be replaced separately. C. Remove the sensor assembly from the engine.

Illustration 3

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Exploded view of the engine speed/timing sensors (4) O-ring seals

D. Ensure that one O-ring (4) is installed on each sensor. Check the O-rings for damage. Replace the O-rings, if necessary. Results: • OK - The sensor assembly's components are OK. Repair: Perform the following procedure in order to properly install the sensor assembly: 1. Lubricate each O-ring with engine oil. 2. Fully seat the sensor assembly in the engine. Note: If the sensor assembly will not fully seat into the engine, replace the sensor assembly. 3. Tighten the bracket bolt. 4. Connect the sensor's electrical connectors. that the connectors are latched on both sides. 5. Ensure that the harness is properly secured, and that the tie-wraps are placed in the correct location. Proceed to Test Step 3. • Not OK - At least one of the sensor assembly's components is not OK. Repair: Obtain a new sensor assembly. Perform the following procedure in order to properly install the sensor assembly: 5. Lubricate each O-ring with engine oil.

2. Fully seat the sensor assembly in the engine. Note: If the sensor assembly will not fully seat into the engine, replace the sensor assembly. 3. Tighten the bracket bolt. 4. Connect the sensor's electrical connectors. that the connectors are latched on both sides. 5. Ensure that the harness is properly secured, and that the tie-wraps are placed in the correct location. that the problem is resolved. STOP Test Step 3. Inspect the Electrical Connectors and the Wiring

Illustration 4

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Left side engine view (typical example) (5) J401/P401 connector for the primary engine speed/timing sensor (6) J402/P402 connector for the secondary engine speed/timing sensor (7) J2/P2 ECM connector

A. Thoroughly inspect connectors (5), (6), and (7). Refer to Troubleshooting, "Electrical Connectors - Inspect".

Illustration 5

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Left side view (P2-48) Primary engine speed/timing sensor + (P2-49) Primary engine speed/timing sensor (P2-58) Secondary engine speed/timing sensor + (P2-59) Secondary engine speed/timing sensor -

B. Perform a 45 N (10 lb) pull test on each of the wires that are associated with the engine speed/timing sensors. C. Check the allen head screw on each ECM connector for the proper torque. Refer to Troubleshooting, "Electrical Connectors - Inspect" for the correct torque values. D. Check the harness and the wiring for abrasion and for pinch points from each sensor back to the ECM.

Expected Result: All of the connectors, pins and sockets are completely coupled and/or inserted and the harness and wiring are free of corrosion, of abrasion and of pinch points. Results: • OK - The harness and connectors appear to be OK. Proceed to Test Step 4. • Not OK - The connectors and/or wiring are not OK. Repair: Repair the wiring and/or the connectors. Replace parts, if necessary. Ensure that all of the seals are properly in place and ensure that the connectors are completely coupled. that the repair eliminates the problem. STOP Test Step 4. Measure the Sensor Resistance through the Engine Harness A. Disconnect the J2/P2 ECM connector. B. If you are troubleshooting a problem with the primary engine speed/timing sensor, perform the following procedure: a. Measure the sensor's resistance between P2-48 (primary engine speed/timing +) and P2-49 (primary engine speed/timing -). b. Check for an intermittent open circuit or for a short circuit by moving the harness while you take the resistance measurement. Pull the wires that are directly behind the sensor or shake the wires that are directly behind the sensor. Resistance ... 75 to 230 Ohms C. If you are troubleshooting a problem with the secondary engine speed/timing sensor, perform the following procedure: a. Measure the sensor's resistance between P2-58 (secondary engine speed/timing +) and P2-59 (secondary engine speed/timing -). b. Check for an intermittent open circuit or for a short circuit by moving the harness while you take the resistance measurement. Pull the wires that are directly behind the sensor or shake the wires that are directly behind the sensor. Resistance ... 600 to 1800 Ohms Expected Result: The resistance measurement is within the specifications. Results: • OK - The resistance measurement is within the specifications. Repair: The sensors and the harness are OK. Replace the ECM. Refer to Troubleshooting, "Replacing the ECM" for detailed instructions. STOP

•

Not OK - The readings are not within the specifications. The sensor resistance is not within the acceptable range when the sensor resistance is measured through the engine harness. Proceed to Test Step 5.

Test Step 5. Measure the Resistance of the Sensor A. Disconnect the harness connector for the suspect sensor. B. Thoroughly inspect the sensor's connectors. Refer to Troubleshooting, "Electrical Connectors - Inspect". C. Measure the sensor's resistance between terminals A and B. Expected Result: For the primary engine speed/timing sensor, the resistance measurement is between 75 and 230 Ohms. For the secondary engine speed/timing sensor, the resistance measurement is between 600 and 1800 Ohms. Results: • OK - The reading is within the specification. There is a problem with the wiring between the engine speed/timing sensor and the ECM. There may be a problem with a connector. Repair: Repair the wiring and/or the connector. Replace parts, if necessary. that the problem is resolved. •

STOP Not OK - The reading is not within the specification. There is an electrical problem with the engine speed/timing sensor. Repair: Perform the following procedure in order to check and install the new sensor assembly: 1. Before you install the new sensor assembly, measure the resistance of the new sensors. If the resistance measurements of the new sensors are within the specifications, install the new sensor assembly in the engine according to the following procedure: a. Loosen the bolt and remove the bolt that holds the sensor to the engine. b. Ensure that an O-ring is installed on the new sensor assembly. that the O-ring is free of damage. c. Seat the sensor and tighten the bolt. If the sensor will not seat, replace the sensor. d. Ensure that the harness is secured in the proper location. 2. that the repair eliminates the problem. STOP

Injection Actuation Pressure Sensor - Test SMCS - 1250-081; 1256-081 System Operation Description: Use this procedure to troubleshoot any suspect problems with the injection actuation pressure sensor. Use this procedure to troubleshoot the 164-02 Injector Actuation Pressure signal erratic that is active. Note: This procedure can check the accuracy of the injection actuation pressure sensor against a pressure gauge. The injection actuation pressure sensor detects the pressure of the oil in the high pressure oil manifold. The signal from the injection actuation pressure sensor is supplied to the Electronic Control Module (ECM). The ECM uses the signal from the injection actuation pressure sensor to calculate the control signal for the injection actuation pressure control valve.

Illustration 1

g01182972

Schematic for the injection actuation pressure sensor Test Step 1. Check for Active Diagnostic Codes A. Connect the Caterpillar Electronic Technician (ET) to the service tool connector. Refer to Troubleshooting, "Electronic Service Tool". B. Turn the keyswitch to the ON position. Note: C. Observe the "Active Diagnostic" screen on Cat ET. Wait at least 15 seconds so that any codes may become active. Look for an active 164-02 diagnostic code. Note: If a 164-03 Injector Actuation Pressure voltage high or a 164-04 Injector Actuation Pressure voltage low is active, refer to Troubleshooting, "Engine Pressure Sensor Open or Short Circuit - Test". Expected Result: The 164-02 diagnostic code is active. Results: • Active code - The 164-02 diagnostic code is active. Proceed to Test Step 3.

•

No active code - The 164-02 diagnostic code is not active. Proceed to Test Step 2.

Test Step 2. Try to Start the Engine Try to start the engine. Expected Result: The engine starts. Results: • OK - The engine starts. There are no active codes for the injection actuation pressure sensor and the engine starts. Repair: There may be an intermittent problem in a harness that is causing the code to be logged. Refer to Troubleshooting, "Electrical Inspectors - Inspect". •

STOP Not OK - The engine does not start. Repair: Refer to Troubleshooting, "Engine Cranks but Will Not Start".

STOP Test Step 3. Inspect the Electrical Connectors and the Wiring A. Turn the keyswitch to the OFF position. B.

Illustration 2 Left side engine view (typical component locations) (1) Injection Actuation Pressure Control Valve (IAPCV) (2) Injection actuation pressure sensor

g01182300

(3) J2/P2 ECM connector (4) Pressure port for high pressure oil supply (5) Low pressure oil line

Illustration 3

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Left side engine view (typical example) (1) J500/P500 Injection actuation pressure control valve connector (2) Injection actuation pressure sensor (3) J2/P2 ECM connector

Note: There are two possible locations for the injection actuation pressure sensor. Refer to Illustrations 2and 3. B. Thoroughly inspect the connectors for sensors (1) and (2) . Also, thoroughly inspect connectors (3) . Refer to Troubleshooting, "Electrical Connectors - Inspect".

Illustration 4

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P2 terminals that are associated with the injection actuation pressure sensor (P2-2) +5 VDC (P2-3) Return (P2-27) Injection actuation pressure sensor

Illustration 5

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Connectors for the injection actuation pressure sensor (A) +5 V Supply (B) Return (C) Signal

C. Perform a 45 N (10 lb) pull test on each of the wires that are associated with the injection actuation pressure sensor. D. Check the torque of the allen head screws for the ECM connectors. Refer to Troubleshooting, "Electrical Connectors - Inspect" for the correct torque values. E. Check the harness and wiring for abrasion and for pinch points from the sensor back to the ECM. Expected Result: All connectors, pins, and sockets are completely coupled and/or inserted. The harness and wiring are free of corrosion, of abrasion, and of pinch points. Results: • OK - The connectors and wiring are OK. Proceed to Test Step 4. • Not OK - There is a problem in the wiring and/or a connector. Repair: Repair the wiring and/or the connector. Replace parts, if necessary. Ensure that all of the seals are properly in place and ensure that the connectors are completely coupled. that the problem is resolved. STOP Test Step 4. Check the Status of the Sensor A. Turn the keyswitch to the ON position. B. Check the value of the "Injection Actuation Pressure" on Cat ET.

Note: If a 164-03 code is active or a 164-04 code is active, the status for the injection actuation pressure will default to 17500 kPa (2538 psi). Expected Result: The value of the "Injection Actuation Pressure" is 0 kPa (0 psi). Results: • OK - The status for the injection actuation pressure is 0 kPa (0 psi). Proceed to Test Step 6. • Not OK - The status for the injection actuation pressure is above 0 kPa (0 psi). Proceed to Test Step 5. Test Step 5. Check the Voltage Supply to the Injection Actuation Pressure Sensor A. Turn the keyswitch to the OFF position. B. Disconnect the injection actuation pressure sensor at the harness connector. C. Turn the keyswitch to the ON position. D. Measure the voltage between terminals A and B on the harness side of the connectors for the injection actuation pressure sensor. Expected Result: The voltage reading is 5.0 ± 0.2 VDC. Results: • OK - The voltage is within the specified range. The sensor is receiving supply voltage. Proceed to Test Step 6. • Not OK - The voltage is not within the specified range. Repair: Refer to Troubleshooting, "5 Volt Engine Pressure Sensor Supply Circuit - Test". STOP Test Step 6. Compare the Sensor's Output to a Pressure Gauge A. Turn the keyswitch to the OFF position. B. Install a 8T-0852 Pressure Gauge in one of the unused oil ports in the high pressure oil rail on the left side of the cylinder head. C. Start the engine. D. Go to the "Injection Actuation Pressure Test" on the diagnostic menu of Cat ET. E. Start the "Injection Actuation Pressure Test". F. Refer to Table 2. Observe the value of the "Injection Actuation Pressure" on Cat ET. Vary the engine speed in order to obtain each "Injection Actuation Pressure" value that is listed in the Table. For each pressure value, observe the reading on the pressure gauge. Table 1 Pressure Reading from Service Tool

Range of Readings from Pressure Gauge

6000 kPa (870 psi)

4000-7800 kPa (580-1130 psi)

10000 kPa (1450 psi)

8000-11800 kPa (1160-1710 psi)

15000 kPa (2175 psi)

13000-16800 kPa (1885-2435 psi)

23000 kPa (3336 psi)

21000-24800 kPa (3045-3595 psi)

Expected Result: Each value on the pressure gauge is within the specification. Results: • OK - Each value on the pressure gauge is within the specification. The injection actuation pressure sensor and the ECM are working properly. Repair: The problem appears to be resolved. The original diagnostic code was probably caused by an intermittent problem in an electrical connector. If the code continues to be logged, refer to Troubleshooting, "Electrical Connectors - Inspect". •

STOP Not OK - At least one of the values on the pressure gauge is not within the specification. Repair: Install a new injection actuation pressure sensor and repeat the test.If the new sensor corrects the problem, leave the new sensor in place.If the new sensor does not correct the problem, the pressure gauge is faulty. Obtain a new pressure gauge and repeat the test. STOP

Injection Actuation Pressure Control Valve Circuit - Test SMCS - 1714-038 System Operation Description: Use the following information to troubleshoot the system when there is an active 42-11 Inject Actuation Control Valve open/short. Note: Do not use this procedure for a 164-11 Injector Actuation Press Sensor mechanical failure that is active unless you are directed to this procedure from another section of this document. The Injection Actuation Pressure Control Valve (IAPCV) supplies control oil pressure to the spool valve in the high pressure oil pump. The spool valve is used to regulate the flow of high pressure oil to the injectors. Excess flow is discharged back to the sump by the spool valve through the low pressure oil line.

The high pressure oil is directed from the high pressure oil pump to the high pressure oil manifold via a high pressure oil line. The injection actuation pressure sensor detects the pressure of the oil in the high pressure oil manifold. The signal from the injection actuation pressure sensor is supplied to the Electronic Control Module (ECM). The pressure of the oil that is in the high pressure oil manifold controls the injection pressure of the fuel. A larger fuel demand by the engine requires a higher fuel injection pressure. A smaller demand requires a lower pressure. The ECM software contains performance maps that define the desired actuation pressure for every engine operating condition. The ECM sends a control current to the IAPCV in order to adjust the pressure of the high pressure oil that is supplied to the injectors. The ECM calculates the control current to the IAPCV by using the engine speed sensor signal, the throttle position signal, and the signal from the injection actuation pressure sensor.

Illustration 1 Schematic for the injection actuation pressure control valve

Test Step 1. Inspect the Electrical Connectors and the Wiring A. Remove power from the ECM.

g01157164

Illustration 2

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Left side engine view (typical component locations) (1) Injection Actuation Pressure Control Valve (IAPCV) (2) Injection actuation pressure sensor (3) J2/P2 ECM connector (4) Pressure fitting for high pressure oil supply (5) Line for low pressure return oil

B. Thoroughly inspect the connectors for sensors (1) and (2). Also, thoroughly inspect connectors (3). Refer to Troubleshooting, "Electrical Connectors - Inspect".

Illustration 3

g01151730

P2 terminations for the IAPCV (P2-61) IAP control valve (P2-62) Return

C. Perform a 45 N (10 lb) pull test on each of the wires that are associated with the IAPCV. D. Check the allen head screw on each ECM connector for the proper torque. Refer to Troubleshooting, "Electrical Connectors - Inspect" for the correct torque value. E. Check the harness and wiring for abrasion and for pinch points from the IAPCV back to the ECM. Note: Ensure that the seal is installed on the harness connector for the injection actuation pressure control valve. Expected Result:

All connectors, pins, and sockets are completely coupled and/or inserted. The harness and wiring are free of corrosion, of abrasion, and of pinch points. Results: • OK - The connectors and the wiring appear to be OK. Proceed to Test Step 2. •

Not OK - There is a problem with the connectors and/or the wiring. Repair: Repair the connectors or wiring and/or replace the connectors or wiring. Ensure that all of the seals are properly in place and ensure that the connectors are completely coupled. that the repair eliminates the problem.

STOP Test Step 2. Check for Active Diagnostic Codes A. Connect the Caterpillar Electronic Technician (ET) to the service tool connector. Refer to Troubleshooting, "Electronic Service Tools". B. Restore power to the ECM. C. Start the engine. D. Observe the "Active Diagnostic" screen on Cat ET. Wait at least 30 seconds so that any codes may become active. Look for a 42-11 diagnostic code that is active. Expected Result: There is an active 42-11. Results: • Active code - The code is active. There is a problem in the circuit for the IAPCV. Proceed to Test Step 3. • No active codes - The code is not active. Repair: If the above code is logged and the engine is not running properly, refer to Troubleshooting, "Troubleshooting Without a Diagnostic Code".If the engine is running properly at this time, there may be an intermittent problem in a harness that is causing the codes to be logged. Refer to Troubleshooting, "Electrical Connectors - Inspect". STOP Test Step 3. Measure the Resistance of the Solenoid for the Injection Actuation Pressure Control Valve A. Remove power from the ECM. B. Disconnect the J500/P500 connectors. Note: Ensure that the seal on the P500 connector remains on the connector when the connector is disconnected. C. Measure the resistance between terminals P500-1 (IAPCV signal) and P500-2 (IAPCV return) on the IAPCV. Record the value of the resistance measurement. Expected Result: The resistance measurement is between 6.5 and 10.5 Ohms.

Results: • OK - The resistance measurement is between 6.5 and 10.5 Ohms. Connect the J500/P500 connectors. Proceed to Test Step 4. • Not OK - The resistance measurement is not between 6.5 and 10.5 Ohms. The solenoid's resistance is not within the specification. Repair: Replace the solenoid. that the problem is resolved. STOP Test Step 4. Check the Harness for an Open Circuit A. Remove power from the ECM. B. Disconnect the J2/P2 ECM connector. C. Measure the resistance between terminals P2-61 (IAPCV signal) and P2-62 (IAPCV return). Expected Result: The resistance measurement is within two Ohms of the value that was measured in the previous test step. Results: • OK - The resistance measurement is within two Ohms of the value that was measured in the previous test step. Proceed to Test Step 5. • Not OK - The resistance measurement is not within two Ohms of the value that was measured in the previous test step. Repair: There is a problem with the wiring harness. There may be a problem with a connector. Repair the wiring and/or the connector. Replace parts, if necessary. that the problem is resolved. STOP Test Step 5. Check the Wiring for a Short Circuit A. Disconnect the J500/P500 connectors. Note: Ensure that the seal on the P500 connector remains on the connector when the connector is disconnected. B. Disconnect the P1 connector. C. Measure the resistance between the points that are listed in Table 1. Be sure to wiggle the wires in the harnesses as you make each resistance measurement. Table 1 Resistance Measurements for the Wiring Harness Connector and Terminal P2-61 (IAPCV signal)

Terminal All of the other terminals on the P2 connector

All of the terminals on the P1 connector Engine ground stud All of the other terminals on the P2 connector P2-62 (IAPCV Return)

All of the terminals on the P1 connector Engine ground stud

Expected Result: All of the resistance measurements indicate an open circuit. Results: • OK - All of the resistance measurements indicate an open circuit. There does not appear to be a short in the harness. Proceed to Test Step 6. • Not OK - At least one resistance measurement does not indicate an open circuit. There is a problem with a wiring harness. There may be a problem with a connector. Repair: Repair the wiring and/or the connector. Replace parts, if necessary. that the problem is resolved. STOP Test Step 6. Check the ECM by using "Injection Act Press Driver Test" Note: This test step may activate additional diagnostic codes. Ignore the codes and monitor the test lamp. Clear the codes at the end of the test step. A. that the J500/P500 connectors are disconnected. Note: Do not insert any wire that is larger than 18 AWG into the J500 harness connector. Do not insert the probe for the voltage test lamp into the harness connector. These actions will spread the sockets of the connector which will damage the connector. Damaged connectors could cause intermittent connections. B. Insert a connector pin into each socket of the J500 harness connector. C. Connect a voltage test lamp to the connector pins that are inserted in the J500 connector. Crank the engine and observe the test lamp. Expected Result: The voltage test lamp illuminates when the engine is cranking. Results: • OK - The voltage test lamp illuminates when the engine is cranking. Remove the connector pins from the P500 connector. Connect all of the electrical connectors. Clear any diagnostic codes. Proceed to Test Step 7. • Not OK - The voltage test lamp does not illuminate. Repair: Replace the ECM. Refer to Troubleshooting, "Replacing the ECM".

STOP Test Step 7. Perform the "Injection Actuation Pressure Test" A. Disconnect the J500/P500 connectors. B. Crank the engine three times at 30 seconds intervals. This will purge the air from the system. C. Connect the J500/P500 connectors. D. Start the engine. E. Run the "Injection Actuation Pressure Test". Note: The "Injection Actuation Pressure Test" is located in the "Diagnostics" menu on Cat ET. Step through all of the pressure ranges. This is not the "Injection Act Press Driver Test". F. After performing the "Injection Actuation Pressure Test", check for an active 42-11 diagnostic code. Expected Result: The test is successful. There are no diagnostic codes. Results: • OK - The problem appears to be resolved. The original problem was probably caused by a poor electrical connection.STOP • Not OK - There is a problem with the IAPCV. Repair: Replace the IAPCV. that the problem is resolved. STOP

Fuel System Pressure - Test SMCS - 1250-081; 1256-081 Table 1 Tools Needed Part Number

Part Name

Quantity

1U-5470 or 198-4240

Engine Pressure Group or Digital Pressure Indicator

1

3Y-2888

Connector

1

3J-1907

O-Ring Seal

1

Note: Both the 5P-2720 Probe Adapter Gp and the 164-2192 Pressure Probe can be used with these tools. Use these additional tools to allow the future installation of pressure probes.

The 1U-5470 Engine Pressure Group or the 198-4240 Digital Pressure Indicator can be used in order to check the engine's fuel pressures. Refer to Special Instruction, SEHS8907, "Using the 1U-5470 Engine Pressure Group " for the instructions that are needed to use the 1U-5470 Engine Pressure Group. Refer to Operation Manual, NEHS0818, "Using the 198-4240 Digital Pressure Indicator " for the instructions that are needed to use the 198-4240 Digital Pressure Indicator.

Illustration 1

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The fuel pressure should be in the following range when the engine is under normal operating conditions and the engine is under load: 400 to 525 kPa (58 to 76 psi) At low idle, the fuel pressure at the fuel filter's inlet should be at the following amount: • 400 to 435 kPa (58 to 64 psi) The fuel pressure to the age for fuel supply should be the same amount, if you subtract the change in pressure (delta P) across the filter. With a new filter, the pressure drop across the fuel filter typically s the following amount: • 35 kPa (5 psi) As abrasive particles collect in the fuel filter, the pressure differential across the filter will increase. When a filter becomes plugged, fuel supply pressure may drop as low as 69 kPa (10 psi) before a •

significant power loss is detected by the operator. Low fuel pressure will cause cavitation and internal damage to the unit injectors. The pressure differential across the fuel filter should not exceed 69 kPa (10 psi). To check the filtered fuel pressure, follow this procedure: 1. Remove the plug (1) from the fuel filter base. 2. Install the connector, the seal, and the engine pressure test group into port (1) in the fuel filter base. Refer to Special Instruction, SEHS8907, "Using the 1U-5470 Engine Pressure Group ".

Electrical Power Supply Circuit - Test SMCS - 1401-038 System Operation Description: This procedure tests whether proper voltage is supplied by machine wiring. Use this procedure to troubleshoot diagnostic codes for the system voltage: • 168-02 Also, use this procedure if you suspect that the Electronic Control Module (ECM) is not receiving the battery supply voltage. Note: The 168-02 code can be generated by rapidly cycling the ignition key switch. Some control modules on the vehicle require this action in order to prompt flash codes. If this occurs, clear the logged diagnostic codes in order to prevent future confusion or an incorrect diagnosis. The ECM receives electrical power (battery voltage) through the wiring that is supplied by the machine harness. The ECM input at connector P1 terminal 70 (keyswitch) receives battery voltage from the keyswitch when the keyswitch is in the ON position or in the START position. When the ECM detects battery voltage at this input, the ECM will power up. When battery voltage is removed from this input, the ECM will power down. The cause of an intermittent power supply to the ECM can occur on either the positive side (unswitched +Battery) or on the negative side (−Battery). Both sides are routed from the ECM to the battery. The three connections for the unswitched +Battery are properly routed through a dedicated protection circuit. Usually, battery power to the cab data link connector is available and the battery power to the cab data link connector is independent of the keyswitch. Therefore, you will be able to power up an electronic service tool, but you may not be able to communicate with the engine ECM. The engine ECM requires the keyswitch to be in the ON position in order to maintain communications. If the keyswitch is in the OFF position, the ECM may power down a short time after you connect the electronic service tool. This is normal. Refer to Troubleshooting, "CAT Data Link Circuit - Test".

For intermittent problems such as intermittent shutdowns that could be caused by machine wiring, temporarily bying the machine wiring may be an effective means of determining the root cause. If the symptoms disappear with the by wiring, the machine wiring is the cause of the problem. A means of bying machine wiring is explained in this test procedure.

Illustration 1 Schematic for ECM battery circuit

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Illustration 2

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Terminal locations for ECM (P1-48) Unswitched +Battery (P1-52) Unswitched +Battery (P1-53) Unswitched +Battery (P1-61) -Battery (P1-63) -Battery (P1-65) -Battery (P1-70) Keyswitch

Test Step 1. Inspect Electrical Connectors and Wiring A. Thoroughly inspect ECM machine harness connector P1, the battery connections, and the connections to the keyswitch. Refer to Troubleshooting, "Electrical Connectors - Inspect".

B. Perform a 45 N (10 lb) pull test on each of the wires in the ECM P1 connector that are associated with the following connections: o Unswitched +Battery (terminals 48, 52, and 53) o −Battery (terminals 61, 63, and 65) Keyswitch (terminal 70) C. Check the allen head screw on each ECM connector and the customer connector for the proper torque. Refer to Troubleshooting, "Electrical Connectors - Inspect" for the correct torque values. D. Check the harness and wiring for abrasions and for pinch points from the battery to the ECM. Also, check the harness and wiring from the keyswitch to the ECM. o

Expected Result: All connectors, pins, and sockets are completely coupled and/or inserted. The harness and wiring are free of corrosion, of abrasion, and/or of pinch points. Results: • OK - Proceed to Test Step 2. • Not OK - There is a problem with the connectors or wiring. Repair: Repair the connectors or wiring and/or replace the connectors or wiring. Ensure that all of the seals are properly in place and ensure that the connectors are completely coupled. STOP Test Step 2. Check the Battery Voltage at the ECM

Illustration 3 ECM breakout T-connector

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A. Disconnect machine harness connector P1 from ECM connector J1 and insert a 70-Terminal breakout T. B. Measure the voltage between P1-52 (unswitched +Battery) and P1-63 (-Battery). C. Measure the voltage between P1-48 (unswitched +Battery) and P1-61 (-Battery). D. Measure the voltage between P1-52 (unswitched +Battery) and P1-63 (-Battery). E. Measure the voltage between P1-53 (unswitched +Battery) and P1-65 (-Battery). F. Turn the keyswitch to the ON position. G. Measure the voltage between P1-70 (keyswitch) and P1-63 (-Battery). Expected Result: The measured voltage is a constant 23.0 to 25.5 VDC with no suspected intermittent problems at this time. Results: • OK - The ECM is receiving the correct voltage. Repair: If an intermittent condition is suspected, refer to Troubleshooting, "Electrical Connectors - Inspect". • • •

STOP Battery voltage is out of range - Proceed to Test Step 3. Intermittent or no voltage - Proceed to Test Step 4. Keyswitch voltage out of range Repair: Trace the wiring for the keyswitch from the ECM through the keyswitch circuit to the batteries. Find the problem and repair the problem. Check the circuit protection for the circuit and for the wiring. that the repairs eliminate the problem.

STOP Test Step 3. Check the Batteries A. Measure no-load battery voltage at the battery posts. B. Load test the batteries. Use the 4C-4911 Battery Load Tester. Refer to Special Instruction, SEHS9249, "Use of 4C-4911 Battery Load Tester for 6, 8 and 12 Volt Lead Acid Batteries" and Special Instruction, SEHS7633, "Battery Test Procedure". Expected Result: The batteries the load test. The measured voltage is at least 23.0 VDC. Results: • OK Repair: Troubleshoot the machine wiring harness and repair the machine wiring harness, as required. that the repairs eliminate the problem. •

STOP Not OK Repair: Recharge or replace the faulty batteries. that the repair eliminates the problem.

STOP Test Step 4. Use the By Harness for the Electronic Service Tool to By the Machine Wiring

Illustration 4

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By harness

A. B. C. D.

E. F.

Note: This by harness is only for test applications. This by harness may be left only temporarily on the vehicle. The by harness can be used in order to determine if the cause of the intermittent problem is interruptions in battery power to the ECM or to the keyswitch circuit. Turn the keyswitch to the OFF position. Disconnect machine harness connector J1/P1 from the ECM. Connect a by harness to ECM connector J1. Remove the 20 amp in-line fuse from the +Battery line of the by harness and connect the unswitched +Battery and −Battery lines directly to the battery posts. Note: This by directly connects the circuit for the keyswitch to the ECM. The ECM will remain powered until the connection to the unswitched battery line "+" is disconnected. Remove the 20 amp fuse from the in-line fuse holder in order to power down the ECM. Do not connect the by to the battery posts without first removing the 20 amp in-line fuse. Do not remove the by from the battery posts without first removing the 20 amp in-line fuse. Connect an electronic service tool to the data link connector of the by harness and that communication is established. Restore all wiring to the original condition after testing.

Expected Result: Installing the by eliminates the problem. Note: The status of the keyswitch will always indicate "On" while the by harness is installed. Results: • OK - The symptoms disappear when the by harness is installed. Also, the symptoms return when the by harness is removed. The problem is in the machine wiring that supplies power to the ECM. Repair the wiring that supplies power to the ECM.STOP •

Not OK Repair: Connect the by to another battery and if the problem is resolved. If the problem is resolved, the problem is with the machine batteries.If the problem still exists, temporarily connect a test ECM. Remove all jumpers and replace all connectors. Recheck the system for active diagnostic codes and repeat the Test Step. If the problem is resolved with the test ECM, reconnect the suspect ECM. If the problem returns with the suspect ECM, replace the ECM. that the repair eliminates the problem. STOP