Circuit/System Verification
WARNING: This page is about a different car, the 2007 GMC Sierra and 2007 Chevrolet Silverado. However, it is still accessible from the selected car via links, so may be relevant.
- If the DTC is history, refer to Charging System Test .
- Start the engine, record the voltage at the battery terminals. Observe the Ignition 1 Signal parameter in the ECM data list. Voltages should not differ by more than 1 volt.
- If more than 1 volt, replace the ECM.