Service function guideCrankshaft Position Variation Learn

This guide explains the crankshaft position variation learn procedure, a service function that teaches the powertrain control module the exact tooth-to-tooth spacing of the crankshaft reluctor wheel so misfire detection stays accurate. It is written for working mechanics and serious DIYers who already have a scan tool capable of bidirectional controls and understand basic engine management. You will learn how the system works, when the learn is required, how to prepare the vehicle, and how to run the full procedure step by step. After finishing, you will be able to execute the learn, verify the result, diagnose a failed learn, and avoid the mistakes that cause repeat comebacks.