Conditions for Setting the DTC

WARNING: This page is about a different car, the 2009 GMC Sierra and 2009 Chevrolet Silverado. However, it is still accessible from the selected car via links, so may be relevant.

The transmission control module has detected an internal overtemperature condition greater than 141°C (286°F) for 2 seconds.
The ignition voltage is greater than 18 volts and the transmission control module temperature is greater than 50°C (122°F).