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.

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.
Ignition OFF. inspect the CMP sensor for correct installation.
- If the CMP sensor is loose, inspect the sensor and the O-ring for damage, and replace as necessary.
Inspect the engine for the following conditions:
- Engine oil for debris
- Camshaft reluctor wheel for damage
- The timing chain, timing chain tensioner, and sprockets for wear or damage
  Repair or replace any worn or damaged components. Refer to Timing Chain, Crankshaft Sprocket, Camshaft Position Actuator and Solenoid Valve Replacement .