Crankshaft Relearn

In order to correctly detect misfires, the PCM must learn the variation between the 7 crankshaft notches. This procedure is performed only once unless a crankshaft or PCM is replaced. The following is a description of what occurs when this procedure is performed with the Scan tool.

When the procedure is initiated, the Scan tool will send a message to the PCM to reset the crankshaft learned adaptive to NO. When the engine coolant temperature is above 70°C (158°F), A/C request is Off and the transaxle in Park or Neutral, the PCM will be prepared to learn the crankshaft notch variation. The accelerator will now have to be manually depressed to fuel cut-off and released. The PCM will cut fuel off near 4000 RPM and will allow the engine to decelerate. The PCM will learn the crankshaft as the engine decelerates. An engine misfire will NOT affect the learning process since the PCM is turning Off the fuel injectors.