GM Service Manual Online
For 1990-2009 cars only
Battery Voltage: The scan tool displays the value of the battery voltage.

Ignition 0: The scan tool displays On when the ignition switch is in the ACCESSORY, RUN or CRANK position.

Ignition 1: The scan tool displays On when the ignition switch is in the RUN or CRANK position.

Ignition 3: The scan tool displays On when the ignition switch is in the RUN position.

Ignition Accessory: The scan tool displays Active when the ignition switch is in the ACCESSORY or RUN position.

Key In Ignition: The scan tool displays Yes when the ignition key is inserted into the ignition switch cylinder. The BCM uses this data to control the chime feature.

SWC Switch Voltage: The scan tool displays the voltage read by BCM at steering wheel control input.

SWC Switch Power: The scan tool display the state of the switched power output to the steering wheel switches and rear wiper.