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.

DTCs P0601, P0602, P0606, P1517, or P1518 are not set.
The ignition switch is in the crank or run position.
The ignition voltage is greater than 5.23 volts.