C0021

ABS/RF Wheel Speed Sensor Circuit Schematic:

CIRCUIT DESCRIPTION
As a toothed ring passes by the wheel speed sensor, changes in the electromagnetic field cause the wheel speed sensor to produce a sinusoidal (AC) voltage signal whose frequency and amplitude is proportional to wheel speed. The magnitude of this signal is directly related to wheel speed and the proximity of the wheel speed sensor to the toothed ring, often referred to as the air gap.

CONDITIONS FOR SETTING DTC
^ No output signal from right front wheel speed sensor for 1.0 second.
^ Excessive right front wheel speed sensor resistance for 1.0 second.

ACTION TAKEN WHEN THE DTC SETS
^ ANTILOCK indicator lamp is illuminated
^ ABS is disabled

NOTE: Diagnostic Trouble Code (DTC) C0021 is a condition latched DTC which indicates the above is true only as long as the condition persists.

CONDITIONS FOR CLEARING THE DTC
^ Conditions for the setting the DTC are repaired and the Scan Tool clear (DTCs) function is used.

WSS Resistance Table:

DIAGNOSTIC AIDS
An intermittent malfunction may be caused by a poor connection, rubbed through wire insulation, or a wire that is broken inside the insulation. Any circuitry that is suspected of causing the intermittent complaint should be thoroughly checked for backed out terminals, improper mating, broken locks, improperly formed or damaged terminals, poor terminal to wiring connections or physical damage to the wiring harness. When inspecting a wheel speed sensor, inspect the sensor terminals and harness connector for corrosion. If evidence of corrosion exists, replace the wheel speed sensor. Resistance of the wheel speed sensor will increase with an increase in sensor temperature. Refer to the table for temperature/resistance values.

DTC C0021 RF Wheel Speed Sensor Circuit Open Or Shorted To Battery (Part 1 Of 2):

DTC C0021 RF Wheel Speed Sensor Circuit Open Or Shorted To Battery (Part 2 Of 2):

TEST DESCRIPTION
The numbers below refer to the step numbers on the chart.
[2] Checks the resistance of the wheel speed sensor circuit.
[3] Checks for an open or high resistance of the wheel speed circuit wiring harness.
[4] Checks the resistance of the wheel speed sensor.