Conditions For Setting DTC

WARNING: This page does not describe the selected car, but rather 13 other vehicles, including the 2003 Hummer H2, 2003 GMC Yukon XL, 2003 GMC Yukon, 2003 GMC Sierra, and 2003 GMC Cab & Chassis Sierra. 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 90° F (34° C) has not been met.