Circuit Description

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.

The Transmission Fluid Pressure (TFP) manual valve position switch consists of 5 normally-open pressure switches. The PCM supplies battery voltage to each range signal. By grounding one or more of these circuits through various combinations of the pressure switches, the PCM detects what manual valve position has been selected, and compares the actual voltage combination of the switches to a TFP manual valve position switch combination table stored in memory. See TFP MANUAL VALVE POSITION SWITCH LOGIC table under DESCRIPTION & OPERATION.

The TFP manual valve position switch assembly cannot distinguish between Park and Neutral because the monitored valve body pressures are identical in both cases. With ignition on and engine off, D2 is indicated. When the transmission in-line 20-way harness connector is disconnected, the ground potential for the 3 range signals to the PCM is removed, and with the ignition on, D2 is indicated.

If the PCM detects an invalid state of the TFP manual valve position switch circuit by deciphering the TFP manual valve position switch inputs, then DTC P1810 sets. For California emissions vehicles and vehicles under 8600 GVW, DTC P1810 is a type "B" DTC. For all other vehicles, DTC P1810 is a type "C" DTC.