900 S Sedan V6-2498cc 2.5L DOHC (1995)
Transmission Speed Sensor: Description and Operation
Input Shaft Speed Sensor
The input shaft speed sensor is mounted in the transmission housing. It provides the transmission control module with information on the speed of the
transmission's input shaft.
The sensor is of electromagnetic (inductive) type and measures the speed of the input shaft after the torque converter (turbine RPM) by means of a
toothed wheel (a drum on the C1 clutch). The sensor's signal voltage, a sine voltage, increases with engine speed. At idling speed it is 1.2-1.4 V A.C. and
at 2,500 RPM it is 2.2 V A.C., measured across the sensor's two pins.
Signal voltage is on pin 12 and signal ground on pin 31.
The resistance across the pins is 300-600 ohms.
The transmission control module uses the input shaft speed signal and vehicle speed to calculate the gear shifting times. Fuel pressure regulation, control
of the lock-up function and engine torque reduction, all of which result in smooth shifting, are based on the information about input shaft RPM and
vehicle speed received by the transmission control module.
The absence of input shaft speed data will activate the limp-home mode.
