Circuit Description
WARNING: This page is about a different car, the 2002 Buick Regal, 2002 Buick Century, 2001 Buick Regal, and 2001 Buick Century. However, it is still accessible from the selected car via links, so may be relevant.
The Automatic Transmission Fluid Pressure (TFP) manual valve position switch consists of six pressure switches (three normally-closed and three normally-open). Ignition voltage is applied to each of the switches. By grounding or opening one or more of these switches with fluid pressure from the manual valve, the PCM can detect which gear range is selected. See TFP LOGIC table.
If the PCM detects an invalid combination of inputs (LOW/HI/LOW or LOW/LOW/LOW), then DTC P1810 sets. If the PCM detects a gear range other than the one indicated, then DTC P1810 sets. DTC P1810 is a type "B" DTC.
TFP LOGIC
| Detected Gear | Signal "A" | Signal "B" | Signal "C" |
|---|---|---|---|
| "P"/"N" | HI | LOW | HI |
| "R" | LOW | LOW | HI |
| "D4" | HI | LOW | LOW |
| "D3" | HI | HI | LOW |
| "D2" | HI | HI | HI |
| "D1" | LOW | HI | HI |
| Illegal | LOW | HI | LOW |
| Illegal | LOW | LOW | LOW |