Vehicle Speed Sensor (VSS)

OPERATION

The Vehicle Speed Sensor (VSS) is a magnetic pick-up that sends a signal to the Powertrain Control Module (PCM). The sensor measures the rotation of the transmission and the PCM determines the corresponding vehicle speed. A faulty speed sensor due to loose connections, bad grounds, high resistance in the circuit, or opens in the circuit can cause the following symptoms.

Related Symptoms

• Overheated transmission
• Increased emissions
• Poor fuel economy
• Stalling on deceleration
• Improper shift points
• Cruise control inoperative

TESTING

1. Turn the ignition switch to the OFF position.
2. Disengage the wiring harness connector from the VSS.
3. Using a Digital Volt-Ohmmeter (DVOM), measure the resistance (ohmmeter function) between the sensor terminals. If the resistance is 190–250 ohms, the sensor is okay.

REMOVAL & INSTALLATION

The VSS is located half-way down the right-hand side of the transmission assembly.

1. Apply the parking brake, block the rear wheels, then raise and safely support the front of the vehicle on jack stands.
2. From under the right-hand side of the vehicle, disengage the wiring harness connector from the VSS.
3. Loosen the VSS hold-down bolt, then pull the VSS out of the transmission housing. To remove the VSS, detach the wiring harness connector from it . . . then remove the hold-down bolt and bracket. . . and slide the sensor out of the transmission case
4. To install:
5. If a new sensor is being installed, transfer the driven gear retainer and gear to the new sensor.
6. Ensure that the O-ring is properly seated in the VSS housing.
7. For ease of assembly, engage the wiring harness connector to the VSS, then insert the VSS into the transmission assembly.
8. Install and tighten the VSS hold-down bolt to 62–88 inch lbs. (7–10 Nm).
9. Lower the vehicle and remove the wheel blocks.