Each wheel has its own wheel speed sensor which sends a small AC electrical signal to the control module. Correct ABS operation depends on accurate wheel speed signals. The vehicle's wheels and tires must all be the same size and type in order to generate accurate signals. If there is a variation between wheel and tire sizes, inaccurate wheel speed signals will be produced.
Honda uses a contactless type of sensor that detects the rotating speed of the wheel. It is constructed of a permanent magnet and a coil. Attached to the rotating parts are gear pulsers (a.k.a. Tone Rings). When these pulsers turn, the magnetic flux around the coil in the wheel sensor alternates its current. This generates voltages in a frequency or wave pattern. These wave pulses are sent to the ABS control unit which identifies the speed of each of the four wheels.
REMOVAL & INSTALLATION
- Raise and safely support the vehicle as necessary for access.
- Make certain the ignition switch is OFF .
- Detach the sensor harness connector.
- Beginning at the connector end, remove grommets, clips or retainers as necessary to free the harness. Take careful note of the placement and routing of the harness; it must be reinstalled in the exact original position.
- Remove the bolt holding the speed sensor to its mounting, then remove the sensor. If it is stuck in place, gently tap on the side of the mounting flange with a hammer and small punch; do not tap on the sensor.
- Place the sensor in position; install the retaining bolts loosely. Route the harness correctly. Avoid twisting or crimping the harness; use the white line on the wires as a guide.
- Once the harness and sensor are correctly but loosely placed, tighten the sensor mounting bolts. Tighten bolts to 16 ft. lbs. (22 Nm).
- Working from the sensor end to the connector, install each clip, retainer, bracket or grommet holding the sensor harness. The harness must not be twisted. Tighten any bolt holding brackets to 84 inch lbs. (10 Nm).
- Attach the wiring connector.
- Use the ABS checker to check for proper signal from the wheel speed sensor.
- Carefully lower the vehicle to the ground.
- Use a non-metallic feeler gauge to measure the gap between the sensor and the pulser.
- Rotate the hub or axle slowly by hand, taking measurements at several locations.
Compare with the following specifications:
Front and Rear: 0.020-0.040 in. (0.5-1.0mm)