Crankshaft Position (CKP) System Variation Not Learned
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 the PCM to accurately compensate for reference period varations. 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.
You likely won't notice any drivability problems.
- Crankshaft position system variation values are not stored in the PCM memory.
- Any engine repair(*) which disturbs crankshaft/harmonic balancer to crankshaft position sensor relationship.
- Crankshaft position sensor replacement.
- Crankshaft balancer replacement.