Diagnostic Aids

WARNING: This page is about a different car, the 2003 Pontiac Grand Prix, 2003 Chevrolet Malibu, and 2003 Buick Century. 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. Check for the following conditions:

Incorrect harness routing near secondary ignition components.
Ignition coil arcing to wiring harness or IC module. Check the ignition coils for cracks, carbon tracking or other signs of damage.
Secondary ignition wires arcing to the wiring harness.
If the DTC is determined to be intermittent, go to INTERMITTENTS in TROUBLE SHOOTING - 3.1L CENTURY, GRAND PRIX & MALIBU article.