Diagnostic Aids

WARNING: This page is about a different car, the 2003 Pontiac Montana, 2003 Oldsmobile Silhouette, and 2003 Chevrolet Venture. 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 IC module. Inspect the ignition coils for the following conditions: Cracks, carbon tracking and other signs of damage.
Secondary ignition wires arcing to the wiring harness.
If the DTC is determined to be intermittent, see INTERMITTENTS in TROUBLE SHOOTING - NO CODES - 3.4L MONTANA, SILHOUETTE & VENTURE article.