How to Test Speed Sensors in a 2000 Blazer

The speed sensors on a 2000 Chevrolet Blazer are part of the anti-lock braking system. The ABS uses the wheel speed sensors to collect speed, acceleration, and braking data. There are a total of three sensors in the system; one at each front wheel and a third sensor mounted on top of the rear differential. When one of these sensors fails, the ABS cannot determine the speed of the vehicle and temporarily deactivates the ABS until the faulty sensor is repaired.

Instructions

1

Navigate to an empty parking lot or vacant street where you can safely test the vehicle. In order to complete this test, youll need to glance down at the scan tool while youre driving, so you need to be in an area free from pedestrians and other objects.

2

Stop the vehicle and shift the transmission into park. Connect the scan tool to the vehicles diagnostic data port. Navigate to the ABS menu on the scan tool and select Live Data. The live data screen shows real-time information from the wheel speed sensors. By reading this screen while moving, you can see whether or not wheel sensors are properly relaying the speed of the vehicle to the ABS computer.

3

Look ahead to make sure the road is clear and then drive the vehicle forward approximately 100 feet. Glance down at the scan tools screen while the vehicle is moving. The readings for each sensor should match the vehicles speedometer. If one of the sensors shows 0 MPH or No Data, then that sensor is not properly communicating with the vehicle.

4

Check the wiring connector on the non-responsive sensor to ensure that its not cut or severed. Its common for the wheel sensor to be in good condition but not operational because its power connection was severed by an accumulation of ice, snow, or other road debris passing through the wheel well and undercarriage area.