Installing a PCMBy Brian A. Marks
The crankshaft position system variation learning feature is used to calculate reference period errors caused by slight tolerance variations in the crankshaft, the crankshaft balancer interupter rings, and the crankshaft sensor hall effect switches. The calculated error allows the PCM to accurately compensate for reference period variations. The crankshaft position system variation learning feature enhances the ability of the PCM to detect misfire events over a wide range of engine speed and load.Please note that this is not a defect or problem - it is simply to help the PCM know exactly what is going on at any particular time.
The crankshaft position system variation values are stored in the PCM non-volatile memory after the crankshaft position system variationlearn procedure has been performed. DTC 1336 set indicates that the crankshaft position system variation values have not been stored in the PCM and the crankshaft position system variationlearn procedure must be performed. The learn procedure is required after the following service procedures have been performed, regardless of whether or not DTC P1336 is set:
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- PCM replacement
- Engine replacement
- Crankshaft replacement
- Crankshaft balancer replacement
- Crankshaft position sensor replacement
- Any engine repair(s) which disturbs the crankshaft/harmonic balancer to crankshaft position sensor relationship.