GM Service Manual Online
For 1990-2009 cars only

The following transmission related indicators and messages may be displayed on the instrument panel cluster (IPC). For a complete listing and description of all vehicle indicators and messages, refer to Indicator/Warning Message Description and Operation in Instrument Panel, Gages, and Console.

Change Transmission Fluid: This illuminates when the transmission control module (TCM) determines that the transmission fluid life is less than 10 percent. Once the TCM determines that the transmission fluid life is greater than 10 percent, the light will go OFF.

Service Transmission: This illuminates when the TCM determines that there is a fault in the transmission.

"Trans Hot Idle Engine": This message is displayed when the TCM detects a transmission fluid temperature (TFT) equal to or greater than 132°C (269°F) for 1 minute.