DTC P1374: 3X Reference Circuit: Description

A 3X reference signal is produced by the Ignition Control (IC) module. The IC module calculates the 3X reference signal by dividing the Crankshaft Position (CKP) sensor 7X pulses by 2 when engine is running and CKP synchronizing pulses are being received. The Powertrain Control Module (PCM) uses the 3X reference signal to calculate the engine RPM and CKP at engine speeds greater than 1600 RPM. The PCM also uses these pulses to initiate injector pulses. The PCM compares the 3X reference pulses to the 24X CKP pulses and the Camshaft Position (CMP) pulses. The engine will continue to start and run using only the 24X CKP and CMP sensor signals. If the PCM detects an incorrect number of pulses on the low resolution engine speed signal circuit, DTC P1374 sets.