Service All-Wheel Drive Light

This light should come on briefly when you turn on the ignition, as a check to show you it is working.
The service all-wheel drive light comes on to indicate that there may be a problem with the drive system and service is required. Malfunctions can be indicated by the system before any problem is apparent, which may prevent serious damage to the vehicle. This system is also designed to assist your GM dealer in correctly diagnosing a malfunction.
See also:
Danger, Warnings, and Cautions
Warning messages found on vehicle labels and in this manual describe hazards
and what to do to avoid or reduce them. Danger indicates a hazard with a high level
of risk which will result in seriou ...
When to Change Engine Oil
This vehicle has a computer system that indicates when
to change the engine oil and filter. This is based on
engine revolutions and engine temperature, and not on
mileage. Based on driving condi ...
Ignition Positions (Key Access)
Ignition Positions (Key Access)
The ignition switch has four different
positions.
Notice:
Using a tool to force the
key to turn in the ignition could
cause damage to the switch or
break t ...
