GM Service Manual Online
For 1990-2009 cars only

Scan Tool Parameter

Data List

Units Displayed

Typical Data Value

Ignition On, Engine Off

DRL Status

Exterior Lamps

Allowed/Not Allowed

Allowed

Battery 1

Exterior Lamps

Volts

12 Volts

Park Lamp Switch

Exterior Lamps

On/Off

Off

Low Beam Switch

Exterior Lamps

On/Off

Off

High Beam Switch

Exterior Lamps

On/Off

Off

Fog Lamp Switch

Exterior Lamps

On/Off

Off

Fog Lamp Relay Command

Exterior Lamps

On/Off

Off

ALC Off Signal

Exterior Lamps

On/Off

Off

ALC Headlamp Relay Command

Exterior Lamps

On/Off

Varies

ALC Park Relay Command

Exterior Lamps

On/Off

Varies

ALC Sensor

Exterior Lamps

Volts

Varies

Day/Night Status

Exterior Lamps

Day/Night/Off/Delay Off

Varies

Right Front Turn Command

Exterior Lamps

Varies

Off

Left Front Turn Command

Exterior Lamps

On/Off

Off

Right Rear Turn Command

Exterior Lamps

On/Off

Off

Left Rear Turn Command

Exterior Lamps

On/Off

Off

Turn/Hazard Input

Exterior Lamps

Volts

Off

Battery 1

Interior Lamps

Volts

12 Volts

I/P Dimmer Input

Interior Lamps

Volts

Varies

I/P Dimmer Percent

Interior Lamps

%

Varies

Interior Lighting Command

Interior Lamps

%

Varies

Interior Lights

Interior Lamps

On/Off

Off

Inadvertent Power Input

Interior Lamps

On/Off

Off

Inadvertent Power Command

Interior Lamps

On/Off

Off