Saturn SL owners may notice the warning message "A/C off for Engine Protection" displayed on their instrument panel, illumination of the check engine light, and the temperature gauge reading cold at all times. This is a feature of the engine that is activated by the power control module when it detects the engine warming up too slowly. The OBD trouble codeP0128may also be stored.

The cause is simply a worn out thermostatthat stays open at all times, preventing the engine from reaching the proper operating temperature.

Replacement of the thermostat will correct the issue.