Conditions for Setting the DTC

WARNING: This page is about a different car, the 2008 GMC Sierra, 2008 GMC Cab & Chassis Sierra, 2008 Chevrolet Silverado, and 2008 Chevrolet Cab & Chassis Silverado. However, it is still accessible from the selected car via links, so may be relevant.

The ECM determines that the EGT sensor 1 is less than 75°C (167°F) of a calibrated threshold, during an active regeneration event.
The condition exists for greater than 5 minutes.