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.

Change Transmission Fluid: This illuminates when the TCM determines that the transmission fluid life is less than 10%. Once the TCM determines that the transmission fluid life is greater than 10% 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.