Compression Brake Solenoid Circuit. Location of the compression brake solenoid. Schematic for the compression brake circuit, страница 3

• OK - A high current diagnostic code (06) is logged at this time. The harness wiring between the valve cover connector for the suspect compression brake solenoid and ECM connector P2 is OK. Proceed to Test Step 7.
• Not OK - A low current diagnostic code 05 is active at this time. The ECM did not detect the short at the valve cover connector for the compression brake solenoid. Proceed to Test Step 4.

Test Step 4. Create a Short Circuit at the ECM

1. Turn the keyswitch to the OFF position.

2. Disconnect the J2/P2 ECM connector.

3. Inspect the terminals on the J2 and P2 ECM connectors for damage.

Note: Refer to the Figure 4 for pin locations.

4. Remove the return wire and the supply wire for the suspect compression brake solenoid from the P2 ECM connector.

5. Fabricate a jumper wire in order to short the two pins for the suspect compression brake solenoid at the ECM. Crimp a socket to each end of the jumper wire. Insert the jumper wire into the P2 ECM connector.

6. Reconnect the P2 ECM connector.

7. Turn the keyswitch to the ON position.

8. Access the "Special Tests" under the "Diagnostics" menu.

9. Start the "Compression Brake Solenoid Test" on Cat ET.

10. Once Cat ET displays the status of the compression brake solenoid, stop the "Compression Brake Solenoid Test".

11. Check for active diagnostic codes and/or logged diagnostic codes that are associated with the compression brake solenoids.

Expected Result:

A high current diagnostic code (06) is logged at this time.

Note: Disconnecting the supply wire for the suspect compression brake solenoid will cause an "Open" in the compression brake solenoid that shares the supply wire with the suspect compression brake solenoid.

Results:

• OK - A high current diagnostic code (06) is logged at this time. The ECM detected the short.

Repair: Check continuity of the supply wire for the suspect compression brake solenoid between the valve cover connector for the suspect compression brake solenoid and P2. If the wire is open, replace the wire.Check continuity of the return wire for the suspect compression brake solenoid between the valve cover connector for the suspect compression brake solenoid and P2. If the wire is open, replace the wire.

STOP

• Not OK - A low current diagnostic code 05 is active at this time. The ECM did not detect the short circuit.

Repair: Replace the ECM. Refer to Troubleshooting, "Replacing the ECM". Verify that the problem is resolved.

STOP

Test Step 5. Open the Wires of the Suspect Compression Brake Solenoid at the Valve Cover Connector

1. Turn the keyswitch to the OFF position.

2. Disconnect the valve cover connector for the suspect compression brake solenoid.

3. Turn the keyswitch to the ON position.

4. Access the "Special Tests" under the "Diagnostics" menu.

5. Start the "Compression Brake Solenoid Test" on Cat ET.

6. Once Cat ET displays the status of the compression brake solenoid, stop the "Compression Brake Solenoid Test".

7. Check for active diagnostic codes and/or logged diagnostic codes that are associated with the compression brake solenoids.

Expected Result:

A low current diagnostic code (05) is active at this time.

Results:

• OK - A low current diagnostic code (05) is active at this time. The ECM detected the open at the valve cover connector for the compression brake solenoid. The harness wiring between the valve cover connector for the suspect compression brake solenoid and ECM connector P2 is OK. Proceed to Test Step 8.
• Not OK - A high current diagnostic code (06) is logged at this time. The ECM did not detect the open at the valve cover connector for the compression brake solenoid. Proceed to Test Step 6.