Circuit Description
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Transmission Fluid Pressure (TFP) position switch assembly consists of 5 normally-open pressure switches. Complete assembly mounts on control valve body. VCM supplies battery voltage to each range switch. VCM grounds one or more range switch signal circuit through various combinations of pressure switches. VCM monitors combinations in order to detect what manual valve position has been selected. VCM compares actual voltage combination of switches to TFP position switch combination values stored in memory. TFP position switch cannot distinguish between Park and Neutral because monitored valve body pressures are identical. DTC P1810 will set if VCM detects an invalid state of TFP position switch. See TFP LOGIC TABLE.
TFP LOGIC
| Gear | Signal "A" | Signal "B" | Signal "C" |
|---|---|---|---|
| Park | Off | On | Off |
| Reverse | On | On | Off |
| Neutral | Off | On | Off |
| Drive/OD | Off | On | On |
| D3/3rd | Off | Off | On |
| D2/2nd | Off | Off | Off |
| D1/Lo | On | Off | Off |
| Illegal | On | Off | On |
| Illegal | On | On | On |