420D, 430D, 432D and 442D Backhoe Loaders Auxiliary Hydraulic Electronic Control System Caterpillar

Prior to replacement of the auxiliary hydraulic ECM, ensure that replacement is absolutely necessary. The ECM is unlikely to fail. Always check that battery voltage is available to the ECM. Battery voltage is required between connector contact 1 and connector contact 3.

Note: The ECM is located behind the operator control panel on the right side of the cab.

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

2. Remove the operator control panel on the right side of the cab.

3. Disconnect the machine harness from the ECM.

4. Remove the ECM.

5. Make sure that the replacement ECM has the correct part number.

6. Install the replacement ECM.

7. Connect the machine harness to the ECM.

8. Turn the disconnect switch and the key start switch to the ON position.

9. Flash the proper software onto the ECM. See Testing and Adjusting, "Electronic Control Module (ECM) - Flash Program".

10. Verify that the ECM is working properly.