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.

No TFP manual valve position switch DTC P1810.
No 4WD low DTC P1875.
The engine is running greater than 400 RPM for greater than 7 seconds.
The system voltage is between 8-18 volts.
No TFP manual valve position switch changes for greater than 6 seconds.
Not in 4WD low.
No 4WD low switch change within 2 seconds.
No AT OSS increase greater than 250 RPM within 2 seconds.