Neutral Profile Correction

In order for the misfire detection system to function correctly, any mechanical inaccuracies in the crankshaft position (CKP) sensor must be learned by the PCM. This information is stored in non-volatile memory (NVM) in the PCM. It is not cleared when the keep alive memory (KAM) is reset.

Neutral profile learning is accomplished using the scan tool any time a PCM is replaced. It should also be relearned any time the CKP sensor or the crankshaft pulse wheel is replaced or major engine repairs have been completed.

To determine if the neutral profile learning has been completed, check the MP_LRN parameter identification (PID) using the scan tool. The PID should read YES if the neutral profile learning has been completed. If the PID reads NO, complete the neutral profile learning prior to diagnosing any misfire DTCs.