Conditions For Running DTC P0503

WARNING: This page is about a different car, the 2002 GMC Yukon XL, 2002 GMC Sierra, 2002 Chevrolet Suburban, and 2002 Chevrolet Silverado. However, it is still accessible from the selected car via links, so may be relevant.

DTC will run under the following conditions:

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.
Not in 4WD Low.
No TFP manual valve position switch changes for greater than 6 seconds.
No 4WD Low switch change within 2 seconds.
No output shaft speed increase greater than 250 RPM within 2 seconds.