Conditions for Running the DTC

WARNING: This page does not describe the selected car, but rather 6 other vehicles, including the 2003 GMC Savana Special, 2003 GMC Savana Camper Special, 2003 GMC Savana, 2003 Chevrolet RV Cutaway, and 2003 Chevrolet Cutaway. However, it is still accessible from the selected car via links, so may be relevant.

No TFP manual valve position switch DTC P1810.
The system voltage is between 8-18 volts.
The engine is running for more than 7 seconds.
The gear range is not PARK or NEUTRAL.
No TFP manual valve position switch changes for greater than 6 seconds.
No 4WD Low switch change within 2 seconds.
No AT OSS increase greater than 250 RPM within 2 seconds.