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:
Security
OnStar provides services like Stolen Vehicle Assistance, Remote Ignition Block,
and Roadside Assistance, if the vehicle is equipped with these services. OnStar
can unlock the vehicle doors remotel ...
Transmission Messages
SERVICE TRANSMISSION
This message displays if there is a problem with the transmission.
See your dealer.
SHIFT TO PARK
This message displays when the transmission needs to be shifted to P (Park). ...
Compass Calibration Procedure
1. Before calibrating the compass, check that the
compass zone is set to the variance zone in
which the vehicle is located. See “Compass
Variance (Zone) Procedure” earlier in this section.
...
