Conditions For Running 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 engine is running for more than 2 seconds.
The engine speed is more than 400 RPM.
The ignition 1 signal is more than 8 volts.
The MAF sensor frequency is stable for more than one second.