Conditions For Running DTC

WARNING: This page does not describe the selected car, but rather 11 other vehicles, including the 2002 GMC Yukon XL, 2002 GMC Yukon, 2002 GMC Sierra, 2002 GMC Cab & Chassis Sierra, and 2002 Chevrolet Tahoe. However, it is still accessible from the selected car via links, so may be relevant.

The ignition voltage is more than 11.7 volts.
The commanded EGR position is more than 0 percent.
The EGR flow test is not active.
The Desired EGR does not change more than 20 percent.