Transaxle Input Speed Sensor (VSS)

The input speed sensor (ISS) is threaded into the transaxle case located near the transaxle fluid filter. The ISS produces an AC voltage of different amplitude and frequency depending on the velocity of the input shaft. The ISS uses 8 total machined notches off the 2nd gear clutch to produce different AC voltage signals. This ISS signal is sent to the PCM, which is used to determine the velocity of the input shaft. A readable input occurs when the input shaft speed is greater than 250 RPM.
The PCM uses the transaxle ISS to monitor the speed of the input shaft. In conjunction with the crankshaft position (CKP) sensor, the PCM can determine the slip across the torque converter. In conjunction with the vehicle speed sensor (VSS), the PCM can determine the slip across the commanded gear clutch pack. The PCM can use this information to determine the torque converter slippage, clutch gear slippage, actual gear ratio or lack of main line hydraulic pressure.