Transmission Fluid Pressure Manual Valve Position Switch Assembly
The Transmission Fluid Pressure (TFP) manual valve position switch assembly is attached to the control valve body. This assembly contains six fluid pressure switches and the transmission fluid temperature sensor.
Five of the fluid pressure switches are normally open. These are used to indicate the position of the manual valve. The PCM uses this information to control line pressure, TCC apply and release, and shift solenoid operation.
The release pressure switch is used as a diagnostic tool to confirm that the TCC is actually off when it has been commanded off by the PCM. This switch is normally closed.
Each fluid pressure switch produces either an open or a ground to the PCM depending on the presence of fluid pressure at the switches. The sequence of open and closed switches produces a combination of voltage readings. The PCM monitors these readings.
The PCM measures TFP manual valve position switch signal voltage from each pin to ground, and compares the voltage to a TFP manual valve position switch combination table stored in the PCM memory. If the PCM does not recognize the switch sequence, a Diagnostic Trouble Code (DTC) will be set as a result. A DTC may also set if the TFP manual valve position switch sequence indicates a gear range selection that conflicts with other sensory inputs to the PCM.
Valid combinations for circuits "A", "B", and "C" are shown in the table. LOW means that the switch is grounded with a resistance less than 50 ohms at zero volts; HI means that the switch is open with a resistance greater than 50 k/ohms at 12 volts. See TFP MANUAL VALVE POSITION SWITCH ASSEMBLY LOGIC table.
Resistance of switch should be measured with the engine running. When the transaxle's pass through connector is disconnected from the vehicle harness while the engine is running, multiple DTCs will set. Clear these DTCs when you are finished with this procedure.
| Gear | Range "A" | Range "B" | Range "C" |
|---|---|---|---|
| Park/Neutral | LOW | HI | HI |
| Reverse | LOW | HI | LOW |
| Drive/OD | LOW | LOW | HI |
| D3/3rd | HI | LOW | HI |
| D2/2nd | HI | LOW | LOW |
| D1/Lo | LOW | LOW | LOW |
| Invalid | HI | HI | HI |
| Invalid | HI | HI | LOW |
TFP MANUAL VALVE POSITION SWITCH ASSEMBLY LOGIC