Circuit Description

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 interrupter rings, and the crankshaft position sensor hall effect switches. The calculated error allows 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 wider range of engine speed and load.

The crankshaft position system variation values are stored in the PCM non-volatile memory after the crankshaft position system variation learn procedure has been performed. DTC P1336 set indicates that the crankshaft position system variation values have not been stored in the PCM and the crankshaft position system variation learn 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:

• PCM replacement
• Engine replacement
• Crankshaft balancer replacement
• Crankshaft position sensor replacement
• Any engine repair(s) which disturbs crankshaft/harmonic balancer to crankshaft position sensor relationship.

Conditions for setting DTC:

• Crankshaft position system variation values are not stored in the PCM memory.