Circuit/System Description
WARNING: This page is about a different car, the 2008 Cadillac CTS. However, it is still accessible from the selected car via links, so may be relevant.
The control solenoid (w/body and TCM) valve assembly has a built-in TCM temperature sensor to detect overtemperature conditions and is not serviced separately. TCM power will produce heat that is absorbed by the internal heat sink. As long as the heat sink and the controller base plate stay below 142°C (288°F), the TCM will stay operational (no overtemperature shut down). This DTC indicates the TCM is in an overtemperature condition and the TCM has shut down to protect it from possible heat damage. This fault is handled inside the TCM and no external circuits are involved. The TCM will remain off until the overtemperature condition no longer exists.