Vehicle Speed Sensor Inspection

Fig 1: Vehicle Speed Sensor, 12 Volt Power Supply & Voltmeter

Courtesy of GENERAL MOTORS CORP.

Remove the connector of vehicle speed sensor, connect 12 volt power supply and voltmeter to the terminal. Do not mistake polarity.

Fig 2: Pulses Per Revolution

Courtesy of GENERAL MOTORS CORP.

Rotate the driven gear.
Observe the voltage.
IMPORTANT: The voltage value will change from approximately 0 to 12 to 0 volts per pulse (1). There will be 4 pulses per revolution (2).
If the result of the inspection is bad, replace the vehicle speed sensor.