3X REFERENCE CIRCUIT
3X reference circuit is produced by Ignition Control Module
(ICM). PCM uses 3X reference signal pulses to calculate engine speed
(RPM) and crankshaft position at engine speed more than 1200 RPM. PCM
uses pulses on this circuit to initiate injector pulses. If PCM
receives incorrect number of pulses on 3X reference circuit, DTC P1374
You likely won't notice any drivability problems.
- Engine running and PCM is receiving 18X reference signal
- Ratio of 18X reference signal pulses to 3X reference signal
pulses received by PCM do not equal 6.
- Ratio of 18X reference signal pulses to camshaft reference
signal pulses received by PCM equals 36.
- Check for faulty 3X reference signal circuit connection at
PCM. Repair as necessary.
- Check for incorrect harness routing near secondary
ignition components, ignition coil arcing to wiring harness or ICM.
- Check ignition coils for cracks, carbon tracking or other signs of
- Check for faulty connections at ICM.
- Replace ICM.