Transaxle Fluid Pressure (TFP) Switch Assembly

The Transaxle Fluid Pressure (TFP) switch assembly is attached to the control valve body. This assembly contains six fluid pressure switches and the Transaxle Fluid Temperature (TFT) sensor.
Five of the fluid pressure switches are normally open. These are used to indicate the position of the manual valve. The PCM/TCM uses this information to control line pressure, TCC apply and release and shift solenoid operation.
The TCC pressure release switch is used as a diagnostic tool to confirm that TCC is actually OFF when it has been commanded OFF by PCM/TCM. This switch is normally closed.
Each fluid pressure switch produces either an open or a ground to the PCM/TCM depending on the presence of fluid pressure at switches. The sequence of open and closed switches produces a combination of voltage readings. The PCM/TCM monitors these readings.
The PCM/TCM measures TFP Sw. signal voltage from each pin to ground and compares voltage to a TFP Sw. combination table stored in PCM/TCM memory. If PCM/TCM does not recognize TFP switch sequence, a diagnostic code will be set as a result. A diagnostic code may also set if the TFP Sw. sequence indicates a gear range selection that conflicts with other sensor inputs to the PCM/TCM.