793F and 797F Off-Highway Truck VIMS and Truck Payload Measurement System Caterpillar

• Make sure that replacement is necessary, an ECM is seldom the cause of a diagnostic code.

• Check that power is available to the ECM, battery voltage is required between the battery+ and battery- pins of the ECM harness connector.

• Contact your Technical Communicator.

New ECMs may or may not be pre-programmed for a particular machine. An unprogrammed ECM must be programmed using Cat^® Electronic Technician (Cat ET). To determine if the ECM is programmed, proceed to Step 7.

Reference: Testing and Adjusting, "ECM Software - Install"

To replace an ECM:

1. Turn OFF the key start switch and the disconnect switch.

2. Disconnect the harness from the ECM.

3. Remove the ECM from the machine.

4. Verify that the replacement ECM has the correct part number.

5. Attach the replacement ECM to the machine.

6. Connect the harness to the replacement ECM.

7. Determine if the replacement ECM is programmed.

   This determination can be done in two different ways. Proceed to 7.a or 7.b.

   1. Enter the component data display mode.

      If the display shows blanks, the ECM is not programmed. See Testing and Adjusting, "ECM Software - Install".

      If the display shows the expected information, the ECM is programmed. Proceed to Step 8.

   2. Connect Cat ET to the machine data link service connector. Cat ET will communicate with the replacement ECM.

      If the ECM is not programmed, Cat ET will indicate the problem.

      If the ECM is programmed, Cat ET will provide access to the proper ECM areas.

8. Configure the ECM.

   Reference: Testing and Adjusting, "ECM - Configure"

   Note: Omitting any configuration procedure will greatly affect performance. Perform all calibration procedures even if the replacement ECM was acquired from a similar machine.