Diagnostic Aids

WARNING: This page does not describe the selected car, but rather 13 other vehicles, including the 2003 Hummer H2, 2003 GMC Yukon XL, 2003 GMC Yukon, 2003 GMC Sierra, and 2003 GMC Cab & Chassis Sierra. However, it is still accessible from the selected car via links, so may be relevant.

The CKP system variation values are not stored in the PCM memory after a learn procedure has been performed. If the actual CKP variation is not within the CKP system variation compensating values stored in the PCM, DTC P0300 may set.

The CKP system variation learn procedure is also required when the following service procedures have been performed, regardless of whether DTC P0315 is set.

An engine replacement.
A PCM replacement.
A harmonic balancer replacement.
A crankshaft replacement.
Any engine repairs which disturb the CKP sensor relationship.

If the CKP system variation learn procedure cannot be performed successfully, check for the following conditions and correct as necessary:

A damaged reluctor wheel.
Excessive crankshaft runout.
A damaged crankshaft.
Interference in the signal circuit of the CKP sensor.
A coolant temperature that is not within the Conditions For Running DTC.
The ignition switch is in the ON position until the battery is drained.
A PCM power disconnect with the ignition ON may erase the stored value and set the DTC P0315.