Transmission Fluid Pressure Manual Valve Position Switch

The Transmission Fluid Pressure (TFP) manual valve position switch consists of 5 pressure switches (2 normally closed and 3 normally open) on the control valve body that sense whether fluid pressure is present in 5 different valve body passages. The combination of switches that are open and closed is used by the PCM in order to determine the actual manual valve position. The TFP manual valve position switch, however, cannot distinguish between PARK and NEUTRAL because the monitored valve body pressures are identical in both cases. The switches are wired to provide 3 signal lines that are monitored by the PCM. These signals are used to help control line pressure, torque converter clutch apply and shift solenoid valve operation. Voltage at each of the signal lines is either zero or 12 volts. The TFT sensor is part of the TFP manual valve position switch assembly.