AFTERCOOLER AS 3916407 - Caterpillar

Illustration 1 g01151945
Schematic of the backup alarm relayThis diagnostic code is associated with the backup alarm relay. This diagnostic code is recorded when the Power Train/Chassis Electronic Control Module (ECM) has determined that the current of the relay is above normal.The possible causes of this diagnostic code are listed:
The energize circuit of the relay is shorted to ground.
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 0144 FMI 06 is active before performing this procedure.Note: Use the 146-4080 Digital Multimeter for the measurements in this procedure.System Response:The backup alarm is always off.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. Ensure that the diagnostic code for the relay is active.
Disconnect the machine harness from the relay.
Observe the status of the diagnostic code. The diagnostic code is active or the diagnostic code is not active.Results:
YES - The diagnostic code is not active. The circuit is correct. The relay is faulty.Repair: Repeat this test order to verify that the relay has failed. Replace the relay. Stop.
NO - The diagnostic code remains active. Proceed to Test Step 2.Test Step 2. CHECK THE SIGNAL CIRCUIT OF THE RELAY FOR A SHORT
Turn the battery disconnect switch and the key start switch to the OFF position.
Disconnect the machine harness from the relay.
Disconnect the machine harness connectors J1 and J2 from the ECM.
At the J1 and J2 machine harness connectors for the ECM, measure the resistance from the signal contact of the relay J2-5 (wire 321-BR) to all possible sources of frame ground.Expected Result:Each resistance should be greater than 5 ohms.Results:
YES - The machine harness is correct. Proceed to Test Step 3.
NO - There is a short in the machine harness. The short is between the signal contact of the relay and the circuit with the low resistance measurement.Repair: Repair the machine harness or replace the machine harness. Stop.Test Step 3. CHECK IF THE DIAGNOSTIC CODE REMAINS
Inspect the contacts and clean the contacts of the harness connectors.
Reconnect all harness connectors.
Turn the battery disconnect switch and the key start switch to the ON position.
Clear all of the inactive diagnostic codes.
Operate the machine.
Check the status of the CID 0144 FMI 06.Expected Result:The CID 0144 FMI 06 is active.Results:
YES - The CID 0144 FMI 06 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 procedure again. If the cause of the diagnostic code is not found, replace the ECM. Refer to Systems operation, Troubleshooting, Testing and Adjusting, "Electronic Control Module (ECM) - Replace" for the machine that is being serviced. Stop.
NO - The CID 0144 FMI 06 is not active. The diagnostic code does not exist at this time. Repair: