Circuit Description
WARNING: This page is about a different car, the 2004 GMC Sierra, 2004 GMC Cab & Chassis Sierra, 2004 Chevrolet Silverado, and 2004 Chevrolet Cab & Chassis Silverado. However, it is still accessible from the selected car via links, so may be relevant.
The hybrid control module (HCM) monitors Ignition 1, Ignition 0 discrete wires from the ignition switch contacts and the Crank state message from powertrain control module (PCM). If HCM detects a mismatch between ignition switch signals and the Crank state message, it will set the DTC. The following table represents correct HCM power mode data:
Valid States
| Ignition Switch Position | HCM and BCM inputs and Scan Tool Display | ||
|---|---|---|---|
| Ignition 0 | Ignition 1 | Crank State | |
| OFF | Off | Off | False |
| UNLOCK | On | Off | False |
| ACC | On | Off | False |
| ON | On | On | False |
| START | On | On | True |