Input Speed Sensor

42LE - Automatic Transmission
SPEED SENSOR - INPUT
DESCRIPTION










The Input Speed Sensor is a two-wire magnetic pickup device that generates AC signals as rotation occurs. It is threaded into the transaxle case (Fig. 382), sealed with an O-ring (Fig. 383), and is considered a primary input to the Powertrain Control Module (PCM).






OPERATION
The Input Speed Sensor provides information on how fast the input shaft is rotating. As the teeth of the input clutch hub pass by the sensor coil (Fig. 384), an AC voltage is generated and sent to the PCM. The PCM interprets this information as input shaft rpm.

The PCM compares the input speed signal with output speed signal to determine the following:
- Transmission gear ratio
- Speed ratio error detection
- CVI calculation

The PCM also compares the input speed signal and the engine speed signal to determine the following:
- Torque converter clutch slippage
- Torque converter element speed ratio