Circuit/System Testing
WARNING: This page is about a different car, the 2007 GMC Sierra, 2007 GMC Cab & Chassis Sierra, 2007 Chevrolet Silverado, and 2007 Chevrolet Cab & Chassis Silverado. However, it is still accessible from the selected car via links, so may be relevant.
IMPORTANT:
If you cannot duplicate the condition, operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records.
- Turn OFF the ignition.
- Disconnect the ECM connector.
- Connect a test lamp between the fuel injector positive voltage control circuit and battery voltage. The test lamp should not illuminate.
- If the test lamp illuminates, test the fuel injector positive voltage circuit for a short to ground.
- Connect a test lamp between the affected fuel injector positive voltage control circuit and a ground. The test lamp should not illuminate.
- If the test lamp illuminates, test the fuel injector positive voltage control circuit for a short to voltage.
- Connect a test lamp between the affected fuel injector control circuit and battery voltage. The test lamp should not illuminate.
- If the test lamp illuminates, test both fuel injector control circuits of the affected group for a short to ground.
- Test the affected fuel injector positive voltage control circuit and the fuel injector control circuit for high resistance.
- Test the affected fuel injector for high resistance. Refer to Component Testing in this diagnostic.
- If all circuits test normal, replace the ECM.