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 CIM detects an open, short to ground or short to voltage in the cellular microphone signal circuit for 10 seconds or greater.
The CIM detects an open/high resistance in the drain wire circuit for 10 seconds or greater.