Circuit/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.
IMPORTANT:
You must perform the Circuit/System Verification before proceeding with Circuit/System Testing.
- 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.
- Inspect the engine front cover area or review the service history of the vehicle for any recent repairs involving the timing chain, the timing chain tensioner, the camshaft, the crankshaft, the camshaft actuator, or the sprockets.
- If recent repairs were made, refer to Timing Chain, Crankshaft Sprocket, Camshaft Position Actuator and Solenoid Valve Replacement and inspect the timing chain, the timing chain tensioner, and both sprockets for proper timing alignment or indexing.
- Remove the engine front cover. Refer to Camshaft Position Actuator Replacement
and inspect the camshaft position actuator for wear or damage. Refer to Camshaft Position Actuator Cleaning and Inspection
.
- If any components are worn or damaged, replace as necessary.