Electrical System Testing

WARNING: This page is about a different car, the 2008 GMC Yukon and 2008 Chevrolet Tahoe. However, it is still accessible from the selected car via links, so may be relevant.

Ignition OFF, open the hood to disable the Auto-Stop function. Refer to Hybrid Modes of Operation Description .
Ignition ON, verify the scan tool hood position parameter displays Open.
- If the hood position does not display Open, refer to Diagnostic Trouble Code (DTC) List - Vehicle for DTC P254F.
If DTCs P3401, P3425, P3441, or P3449 are set, refer to DTC P3401, P3425, P3441, or P3449 .
Ignition ON, engine OFF, command each VLOM solenoid ON and OFF using the scan tool output control function. While standing next to the engine compartment, you should be able to hear the solenoid energize and de-energize with each scan tool output control command.

If you cannot hear each solenoids energize and de-energize, refer to Cylinder Deactivation (Active Fuel Management) System Diagnosis .