26SI Series Alternator – Electronic Control Module (ECM) – Replace

Prior to the replacement of the ECM, ensure that replacement is absolutely necessary. The ECM is seldom the cause of a failure. Always check that power is available to all of the contacts of the ECM that are marked with “+ Battery” and “Keyswitch”. Continue Only if all other attempts to isolate the problem have failed. Always consult the dealership’s Technical Communicator for possible consultation with Caterpillar. This consultation may greatly reduce the time required for a repair.

Perform the following in order to replace the ECM:

  1. Disable the supply voltage to the system and confirm no voltage is present at the PL1000E Communication ECM connector.
  1. Disconnect the system harness from the ECM.
  1. Remove the ECM.
  1. Make sure that the replacement ECM is the correct part number.
  1. Install the replacement ECM according to the procedures in Special Instruction, REHS2362.
  1. Verify that the ECM operates correctly.