DTC P1374: 3X Reference Circuit: Description

WARNING: This page is about a different car, the 2002 Pontiac Aztek and 2002 Buick Rendezvous. However, it is still accessible from the selected car via links, so may be relevant.

A 3 X reference signal is produced by the ignition control (IC) module. The IC module calculates the 3 X reference signal by dividing the crankshaft position (CKP) sensor 7 X pulses by 2 when the engine is running and the CKP synchronizing pulses are being received. The Powertrain Control Module (PCM) uses the 3 X reference signal to calculate the engine RPM and the CKP at engine speeds above 1600 RPM. The PCM also uses these pulses to initiate injector pulses. The PCM compares the 3 X reference pulses to the 24 X CKP pulses and the camshaft position (CMP) pulses. The engine will continue to start and run using only the 24 X 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.