Conditions For Setting DTC

WARNING: This page does not describe the selected car, but rather 7 other vehicles, including the 2003 GMC Yukon XL, 2003 GMC Sierra, 2003 GMC Cab & Chassis Sierra, 2003 Chevrolet Suburban, and 2003 Chevrolet Silverado. However, it is still accessible from the selected car via links, so may be relevant.

The PCM detects that the calibrated amount of engine run time has been met.
The calibrated amount of engine air flow has been met.
The engine coolant temperature for Closed Loop of 113° F (45° C) has not been met.