GM Service Manual Online
For 1990-2009 cars only

Body Control Module (BCM)

Battery 1: Displays 0.0-25.5 V. This parameter is the system voltage measured by the BCM at the BCM battery input.

Power Model: Displays OFF/ACCY/RUN/CRANK. This parameter displays the ignition switch position.

Shifter Unlock Fdbk: Displays High/Low. This parameter indicates Low when the mechanical lock is engaged preventing an inadvertent shift out of the PARK position. The Display indicates High when BCM opens the controlled ground circuit of the shift lock control solenoid.

Engine Control Module (ECM)

Battery 1: Displays 0.0-25.5 V. This parameter is the system voltage measured by the BCM at the BCM battery input.

Shifter Inhibit: Displays Low TFT/Normal. On vehicles with the CVT transmission, this parameter indicates the ECM operational status of the transmission. Low TFT indicates the transmission fluid temperature is too low to allow the shift lever out of the PARK position. Normal indicates transmission fluid temperature is warm enough to allow normal shift lever operation.