WHEEL GP-REAR 8X9972 - Caterpillar

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Turn the switch that provides power to the keyswitch input for the ECM to the OFF position.
Turn the breaker for the ECM to the OFF position.Expected Result:A -6 diagnostic code was active for the prelube relay. After creating an open at the prelube relay, a -5 diagnostic code is now active for the prelube relay.Results:
OK - A -6 diagnostic code was active before disconnecting the wire. A -5 diagnostic code became active after disconnecting the wire. The harness and the ECM are OK. The problem may be in the prelube relay.Repair: Check wire 229-BK on terminal 4 of the prelube relay for continuity to engine ground. If wire 229-BK is OK, install a new prelube relay. Verify that there are no active diagnostic codes for the prelube relay. Clear any logged diagnostic codes.STOP
Not OK - A -6 diagnostic code remains active. The short is between the prelube relay and the ECM. Leave the wire A447-GN disconnected. Proceed to Test Step 5.Test Step 4. Create a Short at the Prelube Relay
Turn the switch that provides power to the keyswitch input for the ECM to the OFF position.
Turn the breaker for the ECM to the OFF position.
Install a jumper wire between terminal 3 and terminal 4 on the prelube relay.
Turn the breaker for the ECM to the ON position.
Turn the switch that provides power to the keyswitch input for the ECM to the ON position.
Monitor the active diagnostic code screen on Cat ET. Check the prelube system for an active diagnostic code.Note: Wait at least 30 seconds in order for the diagnostic code to become active.
Select diagnostic tests from Cat ET.
Select the "Override Parameters" screen on Cat ET.
Activate the prelube override.
Monitor the active diagnostic code screen on Cat ET. Check the prelube system for an active diagnostic code.Note: Wait at least 30 seconds in order for the diagnostic code to become active.
Disable the prelube override.
Turn the switch that provides power to the keyswitch input for the ECM to the OFF position.
Turn the breaker for the ECM to the OFF position. Remove the wire jumper.Expected Result:A -6 diagnostic code is active when the jumper wire is installed. A -5 diagnostic code is active when the jumper wire is removed.Results:
OK - A -6 diagnostic code is active when the jumper wire is installed. A -5 diagnostic code is active when the jumper wire is removed. The engine harness and the ECM are OK. The open circuit is in the coil of the prelube relay.Repair: Install the new prelube relay. Clear any logged diagnostic codes.STOP
Not OK - The -5 diagnostic code remains active with the jumper in place. Verify that the wire 229-BK on terminal 4 of the prelube relay has continuity to engine ground. If wire 229-BK has continuity to engine ground, the open circuit is between the ECM and the prelube relay. Proceed to Test Step 5.Test Step 5. Test the Operation of the ECM
Fabricate two jumper wires that are long enough to create a test circuit at the ECM