3500 4x2 Pickup V8-360 5.9L Magnum (1994)
Wheel Speed Sensor: Description and Operation
NOTE: The EBH-5H ABS system uses one wheel speed sensor on each front wheel, and one speed sensor mounted in the rear axle for the rear wheels.
CONSTRUCTION
Each sensor has:
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Metal tone wheel with teeth on its outside diameter
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Magnet/coil pick-up (speed sensor) that is mounted to the knuckle
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Air gap between the tone wheel and the speed sensor assembly
OPERATION
The sensor measures the wheel speed by monitoring a rotating tone wheel. The signal generated by the sensor and tone wheel pair is transmitted to
the Controller - Antilock Brake (CAB).
As the teeth of the tone wheel move through the magnetic field of the sensor, an AC voltage is generated. This signal frequency increases or
decreases proportionally to the speed of the wheel. The CAB monitors this signal to check for a sudden change in single or multiple wheel
decelerations. If the deceleration of one or more wheels is not within a predetermined amount, the antilock module takes control.
Diagnostically, the coil of each wheel speed sensor will have approximately 1000 to 2500 ohms of resistance.
Each front wheel speed is monitored through the speed sensor mounted at the front hub. The rear wheel speed is monitored through the speed
sensor mounted in the rear axle assembly.
The CAB will disable antilock control, complete the antilock warning light circuit, and store trouble codes if it detects a problem with any or all of
the wheel speed sensors:
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Incorrect circuit resistance when checked with no vehicle movement
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Incorrect sensor output during vehicle movement
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Erratic sensor output during vehicle movement
