CARRIER-PLANETARY 1128759 - Caterpillar

Illustration 1 g01233557
Schematic of the start relay magnetic switchThis diagnostic code is associated with the start relay magnetic switch. This diagnostic code is recorded when the Power Train/Chassis Electronic Control Module (ECM) has determined that the current of the relay is below normal.The possible causes of this diagnostic code are listed below:
The energize circuit of the relay is open.
The return circuit of the relay is open.
The relay has failed.
The ECM has failed. This is unlikely.Note: The following test procedure may create other diagnostic codes. Ignore these created diagnostic codes and clear these diagnostic codes when the original diagnostic code has been corrected. Ensure that the diagnostic code of CID 0444 FMI 05 is active before performing this procedure.Note: Use the 146-4080 Digital Multimeter for the measurements in this procedure.System Response:When this diagnostic code is active, the engine start is disabled.Test Step 1. CHECK THE RELAY
Turn the battery disconnect switch and the key start switch to the ON position. Do not start the engine.
Disconnect the relay with the active diagnostic code from the machine harness.
At the machine harness connector for the relay, place a jumper wire from contact 2 (wire H868-WH) to contact 1 (wire 306-GN).
Observe the status of the CID 0444 FMI 05.Expected Result:The CID 0444 FMI 05 remains active. The FMI has not changed and the "05" is still active.Results:
YES - The diagnostic code remains active. The jumper wire does not affect the diagnostic code. Proceed to Test Step 2.
NO - The diagnostic is no longer active. The relay has failed.Repair: The relay has failed. Repeat this Test Step "CHECK THE RELAY" in order to verify the failure of the relay. Replace the relay. Verify that the new relay corrects the problem.STOPTest Step 2. CHECK THE HARNESS FOR AN OPEN
Turn the key start switch and the battery disconnect switch to the OFF position.
Disconnect the machine harness connector(s) from the ECM.
The jumper wire that was installed in the previous test remains in place.
At the machine harness connector, measure the resistance from signal contact J2-7 (wire 306-GN) to contact J2-4 (wire H868-WH).Expected Result:The resistance is less than 5 ohms.Results:
YES - The resistance is less than 5 ohms. The machine harness is correct. Proceed to Test Step 3.
NO - The resistance is greater than 5 ohms. The resistance measurement is not correct. There is an open circuit in the machine harness.Repair: The open circuit is in wire 306-GN or in wire H868-WH of the machine harness. Repair the machine harness or replace the machine harness.STOPTest Step 3. CHECK IF THE DIAGNOSTIC CODE REMAINS
Inspect the contacts of the harness connectors and clean the harness connectors.
Reconnect all harness connectors.
Turn the battery disconnect switch and the key start switch to the ON position.
Operate the machine.
Check the status of the CID 0444 FMI 05.Expected Result:The CID 0444 FMI 05 is active.Results:
YES - The CID 0444 FMI 05 is active. The diagnostic code has not been corrected. The ECM may have failed.Repair: It is unlikely that the ECM has failed. Exit this procedure and perform this