Wheel Speed Sensors
FRONT WHEEL SENSOR
The sensor sends wheel speed information to the ECU where it's speed signals are used to determine when anti-lock control is required. Each wheel speed sensor consists of a magnet surrounded by a coil of wire. Mounted next to each sensor is a toothed ring that rotates along with the brake disc.
As each tooth passes, the magnetic field in the wheel sensor is strengthened momentarily. This field strength change, repeated as each tooth passes the sensor, induces voltage in the wheel speed sensor coil and coaxial cable. The ECU compares the frequency of the AC signals from the wheel speed sensors to detect rapid wheel deceleration, indicating possible wheel locking.
CAUTION: Tire size determines the number of teeth on the front reluctor ring. It's therefore important that the vehicle be equipped with the original equipment tire sizes. Changing tire size could affect system function.
NOTE: Always route these cables in exactly the same position as original manufacture. Electronic noise from improper cable routing can cause improper signals to be sent to the ECU.
Front Axle Wheel Speed Sensors:
REAR WHEEL SPEED SENSOR
Vehicles with ASR have a speed sensor on each of the four wheels.
The single-edged tooth (arrow) and the long cable with a coaxial plug (as on vehicles with ABS) identify the two front axle wheel speed sensors.
Left Rear Wheel Speed Sensor:
The letter E (arrow) on the plug identifies the left rear wheel speed sensor (L6/3).
Right Rear Wheel Speed Sensor:
The letter D (arrow) on the plug identifies the right rear wheel speed sensor (L6/4).
Rear Axle Multiple Circuit Junction Connector:
Plugs D and E of the wheel speed sensors plug into the openings identified by the letters D and E of the rear axle multiple circuit junction connector (X62/8).
Front Axle Wheel Speed Sensors:
The double-edged tooth (arrow) and the long cable with coaxial plug (as on vehicles with ABS) identify the two front axle wheel speed sensors (L6/1, L6/2). The double-edged pickup compensates for wheel bearing play.
Left Rear Wheel Speed Sensor:
The left rear wheel speed sensor (L6/3) is straight, The wire has a female plug connector (L6/3x1).
Right Rear Wheel Speed Sensor:
The right rear wheel speed sensor (L6/4) is angled. The wire has a male plug connector (L6/4x1).
Front Wheel Speed Sensor:
The single-edged too the (see models 124 and 201) and the short cable (approx. 150 min) leading to correctors (X62/14 or X62/15) in the steering knuckle identify the two front wheel speed sensors (L6/1, L6/2).
Left Rear Wheel Speed Sensor:
The left rear wheel speed sensor (L6/3) is angled. The letter E (arrow) identifies the plug.
Right Rear Wheel Speed Sensor:
The right rear wheel speed sensor (L6/4) is angled. The letter D (arrow) identifies the plug.
Rear Axle Multiple Circuit Junction Connector:
Plugs D and E of the wheel speed sensors plug into the openings identified by the letters D and E of the rear axle multiple circuit junction connector (X62/8).
Rear Axle Shaft Flange:
Each rear wheel speed is measured separately at the toothed rear axle shaft flange.
Note:
Select-fit washers are used to determine the gap between the wheel speed sensor and the toothed gear. These should not be lost or interchanged.