Diagnostic Aids

WARNING: This page is about a different car, the 2003 Pontiac Grand Am, 2003 Oldsmobile Alero, 2003 Chevrolet Monte Carlo, and 2003 Chevrolet Impala. However, it is still accessible from the selected car via links, so may be relevant.

DTC P1374 can be caused by secondary components leaking high voltage into the IC module. Inspect for the following conditions:

Incorrect harness routing near secondary ignition components.
Ignition coil arcing to wiring harness or ICM. Inspect the ignition coils for cracks, carbon tracking or other signs of damage.
Secondary ignition wires arcing to the wiring harness.
It the DTC is determined to be intermittent, go to INTERMITTENTS in TROUBLE SHOOTING - NO CODES - 3.4L ALERO, GRAND AM, IMPALA & MONTE CARLO article.