- Start the engine and allow the ECT to reach at least 70°C (158°F).
- Turn the A/C OFF and place the transaxle in Park or Neutral.
- Using the scan tool, perform the CRANKSHAFT POS. VARIATION LEARN procedure.
Crankshaft Position Variation Procedure Explained
When the procedure is initiated, the scan tool will send a message to the PCM to enable crank learn.
Important: The PCM will only learn the crankshaft when the procedure is performed with a scan tool.
When the engine coolant temperature is above 70°C (158°F) with the A/C request OFF and the transaxle in Park or Neutral, the PCM will be ready to learn the crankshaft notch variation. The accelerator will now have to be manually depressed to wide open throttle and released. The PCM will cut fuel off above 4000 RPM and will allow the engine to decelerate. The PCM will learn the crankshaft as the engine decelerates.
If the PCM will not learn the crankshaft, the following are some diagnostic aids that may help to complete the learn procedure:
Excessive Crankshaft Variation Symptom
Scan Tool Display | Possible Causes |
|---|---|
Factors out or range | The reluctor wheel-machining quality, a run out, or an incorrect air gap |
Opposing factors out of range | Disturbance-noise on the crank sensor circuit. Reattempt the learn procedure. |
Sum out of range | The engine is too cold. Run the engine above 70°C (158°F) and reattempt the learn procedure. |
Crank pulse count error | Cam or crank sensor DTC is set. Diagnose that DTC first. |
