Vehicle Speed Sensor Inspection

Fig 1: View Of Vehicle Speed Sensor, 12 Volt Power Supply And 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: Identifying 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.