A Quick Guide for Replacing Your Speed Sensor Harness
After doing an OBD II scan and discovering that your input or output speed sensor has gone bad, the first thing you need to do is to repair the sensor. If you notice, however, that the sensor is still intact, then the trouble may be coming from the speed sensor harness. To fix your car's damaged speed sensor, here's a quick guide that you can use:
Difficulty level: Moderate
Materials to be used:
- Screwdriver set
- Socket set
- Shop towels
- Safety goggles
- Protective gloves
- Jack and jack stands
- New wheel speed sensor harness
Step 1: Park your vehicle on a level ground, and put on the emergency brake. Lift your car using a jack, and allow it to rest on jack stands. Once you've raised your vehicle, loosen the lug nuts and remove the wheel.
Step 2: With the tire removed, look for the mounting bolts of the brake caliper and remove them. Once the bolts are out, grab the caliper, and sway it back and forth to loosen its attachment. Put the caliper aside in a safe area. Never let the caliper hang loose by the brake hose.
Step 3: Uninstall the brake pads, and set them aside in a secure place. Be sure you don't let the grease touch the pads' surface. Loosen and uninstall the mounting bolts of the brake caliper bracket.
Step 4: Get a hammer, and use it to jolt the rotor loose, if needed. Once it's loose enough, remove the brake rotor from the vehicle. You should now be able to see the wheel speed sensor. If you still can't find it, then consult your vehicle manual. Some car models have the sensor connected to the spindle's rear.
Step 5: Take out the sensor mounting bolt using a socket or wrench of the appropriate size. After the disconnecting the sensor, grab it carefully and remove it from the spindle or bearing hub.
Step 6: Look for the connector of the speed sensor wiring; it's usually located near the frame or the upper control arm. Free the safety clasp, and cautiously remove the wiring connector from the speed sensor harness.
Step 7: Grab the replacement speed sensor, and compare it with the stock sensor. Make sure they're a match; otherwise, you may end up with an improper installation and an incorrect sensor operation.
Step 8: After fitting the new speed sensor, the ABS warning light should go out, even if you haven't reset or cleared the codes in the OBD II scan tool. In some vehicles, you might need to use an ABS scan tool to restart the system though this is a rare scenario.
Tips and reminders:
- The wheel speed sensor allows the brake system of your car to monitor and control the rotation speed of each wheel. Since the sensor is prone to damage and failure, it's a must that you replace it once it starts to malfunction.
- When the speed sensor is broken, you will notice a red or yellow warning light in the brake system.