Circuit/System Testing
- Ignition OFF, disconnect the harness connector at the appropriate fuel injector.
- Ignition ON, verify that a test lamp illuminates between the ignition 1 voltage circuit terminal 1 and ground.
- If the test lamp does not illuminate, repair the ignition 1 voltage circuit for a short to ground or an open/high resistance. Replace the fuse if necessary.
- Ignition OFF, connect a J 34730-405 between the control circuit terminal 2 and the ignition 1 voltage circuit terminal 1.
- Engine running, the test lamp should flash.
- If the test lamp is always ON, test the control circuit for a short to ground. If circuit tests normal, replace the ECM.
- If the test lamp is always OFF, test the control circuit for a short to voltage or an open/high resistance. If circuit tests normal, replace the ECM.
- If all circuits test normal, test or replace the fuel injector.