The wheel speed sensor is a critical component of the anti-lock brake system in your 2000 to 2005 Ford Focus. These small devices attach to each wheel on your vehicle and measure the rate of rotation of that wheel. They then send a signal to the ABS control module for proper ABS function. A failing wheel speed sensor adversely affects the ABS, threatening your safety in emergency situations.
Park your Ford Focus on a level surface, activate the emergency brake and place blocks behind the back tires for safety. Disconnect the negative battery cable with a terminal puller.
Raise the vehicle on the side of the wheel speed sensor's location. Remove the wheel and tire assemblies.
Disconnect the speed sensor electrical connections from the wiring harness.
Unscrew the speed sensor mounting nut and remove the sensor from the vehicle.
Reverse the removal process to install the new speed sensor. Torque the sensor mounting nut to 80 inch pounds (nine Nm).
Lower the vehicle safely and reconnect the negative battery cable. Refer to your owner's manual to perform an ABS system check to confirm that you installed the sensor properly.
For front wheel speed sensors, check the o-ring and spacer for damage and replace if necessary. Apply an anti-corrosive sealant to the wheel speed sensor prior to installation to prevent galvanic corrosion.
Never remove the speed sensor with pliers. If corrosion causes the sensor to seize to the differential housing, use a small mallet and punch to remove it by lightly tapping the edge of the sensor ear and rocking the sensor from side to side until it comes loose. Additionally, don't hammer or bang the new wheel speed sensor into the sensor housing. You must push it in by hand. The disconnection of the negative battery cable may interfere with the on board computer function. Upon reconnection, the computer may need to go through a relearning process. Failure to install a wheel speed sensor properly, such as contact with moving parts or stretched sensor cables, can result in ABS failure and threaten your safety. If in doubt, consult a mechanic for correct installation.