Crankshaft Position Sensor System Variation Learn Procedure

The Powertrain Control Module (PCM) uses crankshaft velocity calculations to determine engine misfire and to operate engine misfire self-diagnostics. PCM must know precisely the variation between notches on the crankshaft. PCM contains crankshaft learn procedure which learns the variation between notches on crankshaft. The crankshaft learn procedure must be reset if PCM, crankshaft, or crankshaft position sensor are replaced.
If crankshaft learn procedure is being performed as a result of replacing the crankshaft, reset crankshaft learn procedure using scan tool or Service Stall System (SSS) equipment and manufacturer's instructions. If replacing PCM with a replacement PCM, procedure will be prompted automatically. Allow engine to idle until SERVICE light flashes. Hold engine speed at 3000-4000 RPM. PCM will take 2 engine revolutions to learn crankshaft notch variation.
NOTE: If any Diagnostic Trouble Codes (DTC) exist that relate to an engine misfire, crankshaft learn procedure will not be initiated. Any DTCs for engine misfire must be corrected before performing crankshaft learn procedure.