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C7 and C9 Marine Engines Caterpillar


Injection Actuation Pressure Control Valve Circuit - Test

Usage:

C7 C7D
System Operation Description:

Use this procedure to troubleshoot any suspect problems with the Injection Actuation Pressure Control Valve (IAPCV).

This procedure covers the 42-11 Inject Actuation Control Valve open/short.

The IAPCV is internal to the unit injector hydraulic pump. The IAPCV is a precision displacement control actuator. This actuator changes the pump outlet flow that is based on the control current that is supplied by the Electronic Control Module (ECM). The variable displacement unit injector hydraulic pump pressurizes only the amount of high pressure oil that is needed.

The ECM software contains performance maps. The performance maps have a desired actuation pressure for every engine operating condition. The ECM sends a control current to the IAPCV. This signal creates an actual actuation pressure that matches the desired actuation pressure. If the actual actuation pressure does not match the desired actuation pressure, the ECM will increase the control current or the ECM will decrease the control current to the IAPCV in order to adjust pump outlet flow.

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Illustration 1g01229672

Schematic for the injection actuation pressure control valve

Test Step 1. Inspect the Electrical Connectors and the Wiring

  1. Remove the electrical power from the ECM.
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    Illustration 2g01223470

    Typical left side view

    (1) IAPCV connector

    (2) J2/P2 connectors

  1. Thoroughly inspect connectors (1) and (2). Refer to the diagnostic functional test Troubleshooting, "Electrical Connectors - Inspect".
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    Illustration 3g01223476

    P2 terminations for the IAPCV

    (P2-10) Return

    (P2-20) Control

  1. Perform a 45 N (10 lb) pull test on each of the wires that are associated with the IAPCV.

  1. Check the torque of the allen head screws for the ECM connectors. Refer to the diagnostic functional test Troubleshooting, "Electrical Connectors - Inspect".

  1. 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 are 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.Verify that the repair eliminates the problem.

    STOP

Test Step 2. Check for Active Diagnostic Codes

  1. Connect the Caterpillar Electronic Technician (ET) to the service tool connector. Refer to electronic troubleshootingTroubleshooting, "Electronic Service Tools".

  1. Restore the electrical power to the ECM.

  1. Start the engine.

  1. Observe the "Active Diagnostic" screen on Cat ET. Wait at least 30 seconds so that any codes may become active.

Expected Result:

The 42-11 code is active.

Results:

  • Active code - The 11 code is active. Proceed to Test Step 3.

  • No active codes - Neither of the above codes are active.

    Repair: If the 11 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 the diagnostic functional test Troubleshooting, "Electrical Connectors - Inspect".

    STOP

Test Step 3. Measure the Resistance of the Injection Actuation Pressure Control Valve's Solenoid

  1. Remove the electrical power from the ECM.

  1. Disconnect the connector.

    Note: Ensure that the seal on the IAPCV connector remains on the connector when the connector is disconnected.

  1. Measure the resistance between terminals 1 (Control) and 2 (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 unit injector hydraulic pump. Verify that the problem is resolved.

    STOP

Test Step 4. Check the Wiring for an Open Circuit

  1. Remove the electrical power from the ECM.

  1. Disconnect the J2/P2 connectors.

  1. Measure the resistance between terminals P2-20 (Control) and P2-10 (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. There is a problem with the wiring harness. There may be a problem with a connector.

    Repair: Repair the wiring and/or the connector. Replace parts, if necessary. Verify that the problem is resolved.

    STOP

Test Step 5. Check the Wiring for a Short Circuit

  1. Disconnect the IAPCV harness connector.

    Note: Ensure that the seal on the IAPCV harness connector remains on the connector when the connector is disconnected.

  1. Disconnect the P1 connector.

  1. 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.

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    Table 1
    Resistance Measurements for the Wiring Harness    
    Connector and Terminal     Terminal    
    P2-20 (Control)     All of the other terminals on the P2 connector    
    All of the terminals on the P1 connector
    Engine ground
    P2-10 (Return)     All of the other terminals on the P2 connector    
    All of the terminals on the P1 connector
    Engine ground

Expected Result:

All of the resistance measurements indicate an open circuit.

Results:

  • OK - All of the resistance measurements indicate an open circuit. 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. Verify that the problem is resolved.

    STOP

Test Step 6. Check the ECM by Cranking the Engine

    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.

  1. Verify that the IAPCV harness connector is disconnected.

    Note: Do not insert any wire that is larger than 18 AWG into the IAPCV 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.

  1. Insert a Deutsch connector pin into each socket of the J500 harness connector.

  1. Connect a voltage test lamp to the connector pins that are inserted in the IAPCV harness 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 IAPCV harness 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 when the engine is cranking.

    Repair: Replace the ECM. Refer to electronic troubleshooting Troubleshooting, "Replacing the ECM".

    STOP

Test Step 7. Perform the "Injection Actuation Pressure Test"

  1. Disconnect the IAPCV harness connector.

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    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.

  1. Crank the engine three times at 30 seconds intervals. This will purge the air from the system.

  1. Connect the IAPCV harness connector.

  1. Start the engine.

  1. Run the "Injection Actuation Pressure Test". The "Injection Actuation Pressure Test" is located in the "Diagnostics" menu on Cat ET. Step through all of the pressure ranges.

    Note: This is not the "Injection Act Press Driver Test".

  1. After performing the "Injection Actuation Pressure Test", check for active diagnostic codes.

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 unit injector hydraulic pump. Verify that the problem is resolved.

    STOP

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