Compression Brake Solenoid Circuit. Location of the compression brake solenoid. Schematic for the compression brake circuit, страница 4

Test Step 6. Create an Open at the ECM

1. Turn the keyswitch to the OFF position.

2. Disconnect the 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. Reconnect the P2 ECM connector.

6. Turn the keyswitch to the ON position.

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

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

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

10. 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 ECM.

Repair: Disconnect the P2 ECM connector. Measure the resistance between the supply wire for the suspect compression brake solenoid and every terminal on ECM connector P1 and ECM connector P2. Measure the resistance between the supply wire for the suspect compression brake solenoid and engine ground. If the wire is shorted, replace the wire.Measure the resistance between the return wire for the suspect compression brake solenoid and every terminal on ECM connector P1 and ECM connector P2. If the wire is shorted, replace the wire.

STOP

• Not OK - A high current diagnostic code (06) is logged at this time. The ECM did not detect the open.

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

STOP

Test Step 7. Create a Short Circuit at the Compression Brake Solenoid

1. Turn the keyswitch to the OFF position.

2. Remove the valve cover.

3. Reconnect the valve cover connector.

4. Disconnect the connector on the suspect compression brake solenoid.

5. Inspect the terminals on the solenoid connector for damage.

6. Fabricate a jumper wire in order to short the two wires for the suspect solenoid on the solenoid connector. Crimp a pin to each end of the jumper wire.

7. Make sure that the solenoid connector securely holds the jumper wire.

Note: Worn terminals and/or damaged terminals on the solenoid connector could cause an intermittent "Open".

8. Turn the keyswitch to the ON position.

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

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

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

12. 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.

Results:

• OK - A high current diagnostic code (06) is logged at this time. The harness wiring between the solenoid connector for the suspect compression brake solenoid and ECM connector P2 is OK.

Repair: Temporarily connect a new compression brake solenoid to the harness, but do not install the new compression brake solenoid in the engine. Verify that there are no active diagnostic codes for the compression brake solenoid. If there are no active diagnostic codes for the compression brake solenoid, permanently install the new compression brake solenoid. Clear any logged diagnostic codes.