GMC Sierra Owners Manual
SERVICE 4 WHEEL DRIVE
If the vehicle has four-wheel drive, this message may display if a problem occurs with the four-wheel-drive system. If this message appears, stop as soon as possible and turn off the vehicle.
Make sure the key is in the LOCK/ OFF position for at least one minute and then restart the vehicle and check for the message on the DIC display. If the message is still displayed or appears again when you begin driving, the four-wheel-drive system needs service. See your dealer.
TRANSMISSION HOT IDLE ENGINE
Notice: If you drive the vehicle while the transmission fluid is overheating and the transmission temperature warning is displayed on the instrument panel cluster and/or DIC, you can damage the transmission. This could lead to costly repairs that would not be covered by the warranty. Do not drive the vehicle with overheated transmission fluid or while the transmission temperature warning is displayed.
This message displays and a chime may sound if the transmission fluid in the vehicle gets hot. Driving with the transmission fluid temperature high can cause damage to the vehicle. Stop the vehicle and let it idle to allow the transmission to cool. This message clears and the chime stops when the fluid temperature reaches a safe level.