Chart No. 4, Vehicle Speed Sensor Circuit Test

The vehicle speed sensor is installed within the speedometer and sends pulse signals to the control unit in proportion to vehicle speed. The vehicle speed sensor is a reed switch type of sensor, generating four pulse signals each rotation of the speedometer driven gear.
Check ECU terminal No. 15 on 1990 models or terminal No. 19 on 1991 models, vehicle speed sensor while moving the vehicle forward slowly. Terminal voltage should alternate between 0-0.7 volts to more than 3 volts.