DTC P0315: Crankshaft Position Sensor Variation Not Learned: Description
WARNING: This page is about a different car, the 2003 GMC Sierra and 2003 Chevrolet Silverado. However, it is still accessible from the selected car via links, so may be relevant.
The Crankshaft Position (CKP) system variation learn feature is used to calculate reference period errors caused by slight tolerance variation in the crankshaft and the CKP sensors. The calculated error allows the Powertrain Control Module (PCM) to accurately compensate for reference period variations. This enhances the ability of the PCM to detect misfire events over a wider range of engine speed and load conditions. The PCM stores the CKP system variation values after a learn procedure has been performed. If the PCM detects the CKP system variation values are not stored in the PCM memory, DTC P0315 sets.