Action Taken When the DTC Sets

WARNING: This page is about a different car, the 2010 GMC Sierra, 2010 GMC Cab & Chassis Sierra, 2010 Chevrolet Silverado, and 2010 Chevrolet Cab & Chassis Silverado. However, it is still accessible from the selected car via links, so may be relevant.

DTC P1258 is a Type A DTC.
The engine will operate in the Overheated Engine Protection Operating Mode.
The engine coolant temperature indicator lamp, if equipped, will illuminate.
The driver information center (DIC), if equipped, may display a message.
If the protection mode is active and an ECT sensor DTC sets, the protection mode will activate during the next drive cycle until the ECT sensor DTC runs and passes.