Escort L4-122 2.0L SOHC VIN P SFI (1999)
Wheel Speed Sensor: Description and Operation
The ABS uses four variable-reluctance sensors and toothed anti-lock sensor indicators to determine the rotational speed of each wheel. The sensors
operate on the magnetic induction principle. As the teeth on the indicator rotate past the stationary sensor, a signal proportional to the speed of the
rotation is generated and sent to the anti-lock brake Control module through a twisted pair wire cable and wiring harness.
The anti-lock brake control module monitors the electromechanical components of the system. Malfunction of the ABS will cause the anti-lock brake
control module to shut off or inhibit the system. However, normal power assisted braking remains. Malfunctions are indicated by the yellow ABS
warning indicator inside the vehicle.
The ABS is self-monitoring. When the ignition switch is placed in the RUN position, the anti-lock brake control module will perform a preliminary
self-check on the anti-lock electrical system indicated by a two-to three-second illumination of the yellow ABS warning indicator in the instrument
cluster. At 6.4 km/h (4 mph), the valves and motor will be powered briefly to verify proper function. During vehicle operation, including normal and
anti-lock braking, the anti-lock brake control module monitors all electrical anti-lock functions and some hydraulic operations.
