DTC P1374: Crankshaft Position Sensor 3X Reference Circuit Malfunction: Description

The 3X reference signal is produced by Ignition Control Module (ICM). The ICM calculates the 3X reference signal by dividing the Crankshaft Position (CKP) sensor 18X pulses by 3. This calculation is performed while engine is running and while the CKP sync pulses are being received.

PCM uses the 3X reference signal in order to calculate engine RPM and CKP at engine speeds more than 1200 RPM. PCM also uses the pulses on the circuit in order to initiate injector pulses and constantly monitors the number of pulses on the 3X reference circuit and compares it to the number of 3X reference pulses to the number of 18 X reference pulses and CAM signal pulses being received. If PCM receives an incorrect number of pulses on the 3X reference circuit, DTC P1374 will set and PCM will use the 18X reference signal circuit for fuel and ignition control. The engine will continue to start and run using the 18X reference and CMP input signals only.