BRACKET 3842243 - Caterpillar

Illustration 1 g01151945
Schematic of the backup alarm relayNote: The approximate coil resistance of the relay is 360 ohms at 25 °C (77.0 °F).This diagnostic code is recorded when the Power Train/Chassis Electronic Control Module (ECM) reads the current of the relay circuit as being below the normal operating range (open circuit).The possible causes of this diagnostic code are listed below:
The relay has failed.
There is an open in the circuit.
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 05 is active before performing this procedure.Note: Use the 146-4080 Digital Multimeter for the measurements in this procedure.System Response:The back up alarm will remain off.Test Step 1. CHECK THE RELAY
Turn the 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.
At the machine harness connector for the relay place a jumper wire from connector contact 5 (wire 321-BR) to the connector contact 2 (wire E790-PK).
Observe the status of the diagnostic code. The diagnostic code is active or the diagnostic code is not active.Expected Result:The status of the diagnostic code is active and the status of the diagnostic code is NOT active as the jumper is installed and then removed.Results:
YES - The circuit is correct.Repair: The relay has failed. Repeat the test Step "CHECK THE RELAY" in 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 RELAY CIRCUIT FOR AN OPEN
Turn the key start switch and the disconnect switch to the OFF position.
Disconnect the machine harness connector J1 and J2 from the ECM.
The jumper that was installed in previous Test Step remains in place.
At the J1 and J2 machine harness connectors for the ECM, measure the resistance from connector contact J2-5 (wire 321-BR) to connector contact J1-55 (wire E790-PK(a)).Expected Result:The resistance is less than 5 ohms.Results:
YES - The machine harness is correct. Proceed to Test Step 3.
NO - There is an open circuit in the machine harness.Repair: The open circuit is in the signal wire (321-BR) or in return wire (E790-PK) of the machine harness. Repair the machine harness or replace the machine harness. Stop.Test Step 3. CHECK IF THE DIAGNOSTIC CODE REMAINS
The contacts of the harness connectors should be cleaned and inspected.
Reconnect all of the harness connectors.
Turn the disconnect switch and the key start switch to the ON position.
Clear all of the inactive diagnostic codes.
Operate the machine.
Stop the machine and place the parking brake switch in the ON position.
Observe the status of the diagnostic code. The diagnostic code is active or the diagnostic code is NOT active.Expected Result:The diagnostic code is NO longer active.Results:
YES - The diagnostic code is NO longer active. The diagnostic code does not