GM Service Manual Online
For 1990-2009 cars only

Data

Battery Voltage: The scan tool displays the battery system voltage.

Dimming Potentiometer: The scan tool displays the voltage output of the instrument panel (I/P) dimmer switch based on switch position. The scan tool displays 4.4 volts when the I/P dimmer switch is in the FULL DIM position and 0 volts when the I/P dimmer switch is in the FULL BRIGHT position.

Dimming Potentiometer R: The scan tool displays the reference voltage to the dimming potentiometer. This voltage value is 5.0 volts.

Inputs

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

Courtesy Lamp Switch: The scan tool displays the position of the courtesy lamp switch. The scan tool displays ON when the switch is turned ON. The body control module (BCM) uses this data in controlling the operation of the courtesy lamps.

Driver Door Ajar Sw.: The scan tool displays Off when the driver door is fully closed or On when the door is open or ajar.

Flash to Pass Switch: The scan tool displays the position of the flash to pass switch. The scan tool displays On when the switch is pulled to activate the high beams momentarily while the switch is held.

Headlamp Switch: The scan tool displays the position of the headlamp switch. The scan tool displays Active when the headlamp switch is in the ON position. The BCM uses this data in controlling the operation of the headlamps.

High Beam Switch: The scan tool displays the position of the high beam switch. The scan tool displays On when the switch is used to activate the high beams.

Interior Lamp Defeat Switch: The scan tool displays the position of the courtesy/dome lamp override switch. The scan tool displays Active when the switch is activated requesting the BCM to override the normal interior lamp activation inputs and deactivate the interior lighting.

Key in Ignition: The scan tool displays Yes when the key has been inserted into the ignition switch. The scan tool displays No after the key has been removed.

Park Brake Switch: The scan tool displays the position of the park brake pedal. The scan tool displays Set when the park brake is engaged closing the switch. The BCM uses this data in controlling the operation of the park brake indicator, and the reminder chime feature.

Park Lamp Switch: The scan tool displays the position of the park lamp switch. The scan tool displays Active when the park lamp switch is in the ON position. The BCM uses this data in controlling the operation of the park lamps.

Passenger Door Ajar Sw.: The scan tool displays OFF when any door other than the driver door is fully closed or ON when a door is open or ajar.

Run/Crank: The scan tool displays the position of the ignition switch. The scan tool displays Active when the ignition switch is in the RUN or CRANK position.

Outputs

Backup Lamps: The scan tool displays the commanded state of the body control module (BCM) which directly supplies battery positive voltage to the backup lamps. The scan tool displays On when the BCM activates the backup lamps upon receiving a backup lamp request signal from the powertrain control module (PCM).

Daytime Running Lamps: The scan tool displays the commanded state of the DRL . The scan tool displays Active when the BCM signals the turn/hazard flasher module to illuminate the DRL.

Headlamps On Indicator: The scan tool displays the commanded state of the BCM which directly supplies battery positive voltage to the headlamps on indicator. The scan tool displays On when the BCM activates the headlamps on indicator upon receiving a headlamp request signal from the headlamp switch.

High Beam Relay: The scan tool displays the commanded state of the high beam relay. The scan tool displays On when the BCM allows the high beam relay to go to ground activating the high beam headlamps.

Inadvertent Power: The scan tool displays the state of the inadvertent power battery rundown protection feature of the BCM. The scan tool displays Off when all inadvertent power circuits are functioning normally. The scan tool will display On as soon as a lamp on the inadvertent power circuit is activated.

Park Lamp Relay: The scan tool displays the commanded state of the park lamp relay. The scan tool displays On when the BCM allows the park lamp relay to go to ground to activate the park lamps.