Use this procedure to troubleshoot any suspect problems with the Injection Actuation Pressure Control Valve (IAPCV).
Use this procedure to troubleshoot the following diagnostic codes:
- 42-05 Injector Actuation Valve open circuit
- 42-06 Injector Actuation Valve short to ground
The IAPCV regulates the high pressure oil system that provides hydraulic pressure to the Hydraulically Actuated Electronically Controlled Unit Injectors (HEUI). The injection actuation pressure sensor monitors the pressure of the high pressure oil system. The Electronic Control Module (ECM) adjusts the pulse width modulated signal to the IAPCV in order to regulate the injection pressure. The IAPCV operates on a signal between 0 and 800 mA.
The ECM uses the following criteria in order to determine the desired injection actuation pressure:
- Fuel pressure and fuel temperature
- Injection timing
- Engine speed (rpm)
- Engine operating mode (cold mode, etc.)
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| Illustration 1 | g01137388 |
Schematic for injection actuation pressure control valve | |
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The connection of any electrical equipment and the disconnection of any electrical equipment may cause an explosion hazard which may result in injury or death. Do not connect any electrical equipment or disconnect any electrical equipment in an explosive atmosphere. |
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Test Step 1. Inspect Electrical Connectors and Wiring
- Turn the keyswitch to the OFF position.
- Thoroughly inspect connector (1). Also inspect the connector for control valve (6). Refer to Troubleshooting, "Electrical Connectors - Inspect" for details.
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| Illustration 2 | g01137477 |
Injection actuation pressure control valve and related components (1) Unit injector hydraulic pump (2) J2/P2 ECM connectors (3) Injection actuation pressure sensor (4) High pressure supply lines to cylinder heads (5) Low pressure supply line to pump (6) Injection actuation pressure control valve | |
- Perform a 45 N (10 lb) pull test on each of the wires that are associated with the IAPCV.
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| Illustration 3 | g01137405 |
P2 ECM connector (P2-29) Injection actuation pressure control valve supply (P2-35) Injection actuation pressure control valve return | |
- Check the allen head screw on the ECM connector for the proper torque. Refer to Troubleshooting, "Electrical Connectors - Inspect" for the correct torque values.
- Check the harness and wiring for abrasion and 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 and the harness and wiring are free of corrosion, of abrasion and of pinch points.
Results:
- OK - The connectors and the wiring appear to be in good repair. 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. Verify that the repair eliminates the problem.
STOP
Test Step 2. Measure the Resistance of the Injection Actuation Pressure Control Valve's Solenoid
- Turn the keyswitch to the OFF position.
- Disconnect J46/P46 IAPCV connector.
- Use a multimeter to measure the resistance between J46-1 IAPCV supply and J46-2 IAPCV return on the IAPCV. Record the value that was measured.
Expected Result:
The resistance is between 5 Ohms and 15 Ohms.
Results:
- OK - The resistance is between 5 Ohms and 15 Ohms. The control valve solenoid does not seem to have an open or a short. Connect the J46/P46 IAPCV connector. Proceed to Test Step 3.
- Not OK - The control valve solenoid is open or shorted internally.
Repair: Replace the IAPCV. Verify that the repair eliminates the problem.
STOP
Test Step 3. Measure the Resistance of the Solenoid Through the Engine Harness
- Disconnect the J2/P2 ECM connector.
- Measure the resistance between P2-29 (IAPCV supply) and P2-35 (IAPCV return).
Expected Result:
The resistance should be within two Ohms of the value that was measured in the previous step.
Results:
- OK - The resistance is within two Ohms of the value that was measured in the previous step. The solenoid harness and the connector are OK. There may be a problem with the ECM. Proceed to Test Step 4.
- Not OK - The resistance is not within the acceptable range. One of the wires in the solenoid harness has an open or a short. There may be a problem with the solenoid connector.
Repair: Repair the wire and/or the connector, when possible. Replace parts, if necessary.
Verify that the repair has resolved the problem. Proceed to Test Step 4.
Test Step 4. Check the ECM with the "Injection Act Press Driver Test"
- Disconnect the J2/P2 ECM connector.
- Connect a 40-pin breakout to the J2 ECM connector.
- Connect a voltage test lamp to P2-29 and P2-35 of the breakout.
- Turn the keyswitch to the ON position.
- Connect Caterpillar Electronic Technician (ET) to the service tool connector. Observe the test lamp while you activate the "Injection Act Press Driver Test" in Cat ET.
- Turn the keyswitch to the OFF position.
Expected Result:
The voltage test lamp illuminates when the test is active.
Results:
- OK - The voltage test lamp illuminates. The ECM is operating properly. Proceed to Test Step 5.
- Not OK - The voltage test lamp does not illuminate.
Repair: Replace the ECM. Refer to Troubleshooting, "Replacing the ECM". Verify that the repair resolves the problem.
STOP
Test Step 5. Perform "Injection Actuation Pressure Test"
- Disconnect the J46/P46 IAPCV connector.
- Crank the engine three times at 30 seconds intervals. This will ensure that air is purged from the high pressure fuel system.
- Reconnect the J46/P46 IAPCV connector.
- Start the engine and run the "Injection Actuation Pressure Test". Step through all of the pressure ranges of the test.
Expected Result:
The engine starts and the engine runs smoothly through all of the pressure ranges.
Results:
- OK - The engine runs smoothly.
Repair: The problem has been corrected.
STOP
- Not OK - The engine does not start or the engine does not run smoothly.
Repair: There is a problem with the IAPCV. Replace the IAPCV. Verify that the repair has resolved the problem.
STOP