Circuit/System Testing
WARNING: This page is about a different car, the 2011 GMC Yukon, 2011 Chevrolet Tahoe, and 2011 Cadillac Escalade. However, it is still accessible from the selected car via links, so may be relevant.
- 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 A and ground.
- If the test lamp does not illuminate, test the ignition 1 voltage circuit for a short to ground or an open/high resistance. If the circuit tests normal and the ignition 1 voltage circuit fuse is open, test or replace the fuel injector.
- Connect the J 34730-405 between the control circuit terminal B and the ignition 1 voltage circuit terminal A.
- Engine cranking, verify the test lamp flashes ON and OFF.
- If the test lamp is always ON, test the control circuit for a short to ground. If the circuit tests normal, replace the engine control module (ECM).
- If the test lamp is always OFF, test the control circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the ECM.
- If all circuits test normal, test or replace the fuel injector.