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:
The CKP System Variation Learn Procedure may have to be repeated up to 5 times before the procedure is learned.
- 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.
- Perform the CKP System Variation Learn Procedure. Refer to Crankshaft Position System Variation Learn .
- If the CKP System Variation Learn Procedure cannot be performed successfully, inspect for the following conditions:
- Any worn crankshaft main bearings
- A damaged or misaligned reluctor wheel
- Excessive crankshaft runout
- A damaged crankshaft-Refer to Crankshaft and Bearing Cleaning and Inspection .
- Interference in the signal circuit of the CKP sensor
- The ignition switch is left in the ON position until the battery is discharged
- An ECM power disconnect, with the ignition ON, that may have erased the CKP system variation values and set DTC P0315
- Any debris between the CKP sensor and the reluctor wheel
- If the ECM is still unable to complete the Learn Procedure, replace the ECM.