Circuit Description

24X reference signal is produced by Ignition Control Module (ICM). The ICM calculates 24X signal by filtering Crankshaft Position (CKP) sensor 24X pulses when engine is running and CKP sync pulses are also being received. PCM uses 24X signal to calculate engine RPM and crankshaft position at engine speeds less than 1200 RPM. PCM constantly monitors number of pulses on 24X reference circuit and compares them with number of 3X reference pulses and CAM signal pulses being received. If PCM receives an incorrect number of pulses on 24X circuit, DTC P0336 will set and PCM will use 3X reference signal circuit for fuel and ignition control.