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.
Ignition OFF, disconnect the harness connector at the CKP sensor.
Test for less than 3 ohms between the CKP low reference circuit, terminal B, and ground.
- If greater than the specified value, test the low reference circuit for an open/high resistance. If the circuit tests normal, replace the ECM.
Ignition OFF, inspect the CKP sensor for correct installation.
- If the CKP sensor is loose, inspect the sensor and the O-ring for damage. Replace as necessary.
- If any parts are worn or damaged, replace as necessary.