Circuit/System Verification
WARNING: This page does not describe the selected car, but rather 8 other vehicles, including the 2007 GMC Yukon XL, 2007 GMC Yukon, 2007 Chevrolet Tahoe, 2007 Chevrolet Suburban, and 2007 Chevrolet Avalanche. 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.