Input Shaft Speed Sensor

INPUT SHAFT SPEED SENSOR
The Input Shaft Speed (ISS) sensor is fitted in the transmission housing. It gives the Transmission Control Module (TCM) information about the incoming rpm to the transmission.

The ISS sensor is of the electro-magnetic (inductive) type and measures the incoming rpm after the torque converter (the turbine rpm) by being affected by a toothed pulse wheel (a drum on the C1 clutch). The sensor's signal voltage, a sine voltage, increases with the engine speed. When idling it is 1.2 - 1.4 V and at 2500 rpm it is 2.2 V, measured between pins 2 and 1 on the sensor.

Pin 12 is signal voltage and pin 31 is signal ground. The resistance between pins 2 and 1 on the sensor connector is 300 - 600 ohms.

The TCM uses the ISS rpm signal and the speed of the car to calculate gear shifting times. The information about rpm and speed affects the regulation of fluid pressure, control of the lock-up function and the reduction in torque, which results in smooth shifting of gears.