TOOL 4Z8504 - Caterpillar

Replacing an Electronic Control Module (ECM)
An ECM is seldom the cause of a diagnostic code. Before replacing an ECM: .
Verify that replacement is necessary.
Check that the proper ground and power are available to the ECM.
Flash the suspect module with a correct flash file. Corrupted software or the wrong software may cause an ECM to report diagnostic codes incorrectly. Flashing the software prior to replacement will verify that the failure is not related to corrupted software. See Troubleshooting, "ECM Software - Install".
Contact your "Technical Communicator" at your dealership.Note: New ECM modules are available either programmed for a particular machine or not programmed. The ECM must be programmed for the machine prior to starting this process. See Troubleshooting, "ECM Software - Install".Procedure
Turn the key start switch and the disconnect switch to the OFF position.
Disconnect the harness from the ECM.
Remove the ECM.
Ensure that the replacement ECM has the correct part number.
Install the new ECM.
Connect the harness to the ECM.
Determine whether the ECM has been programmed.
Connect Cat ET to the service tool connector.Cat ET communicates with the ECM.Cat ET indicates whether the ECM has been programmed.
An ECM that has not been programmed, must be programmed. See Troubleshooting, "ECM Software - Install".