DTC A022: Right Front Wheel Speed = 0

RIGHT FRONT WHEEL SPEED = 0





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 whose frequency is proportional to the 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).

Diagnosis
This test checks for the right front wheel speed equal to 0 km/h (0 mph) for greater than 1.6 seconds while the other three wheel speeds are greater than 8 km/h (5 mph) and within 11 km/h (7 mph). This test will not fail if any wheel speed hardware faults (codes A032-A035) have already failed.

Cause(s)
- The sensor is physically damaged.
- The wheel speed input wires are shorted together.
- A sensor harness lead is shorted to voltage.
- A sensor harness lead is shorted to ground.
- There is an open or high resistance in a sensor harness lead. The speed ring is missing.
- The air gap exceeds the required specifications.
- The connector is damaged.
- The electronic brake control module (EBCM) is faulty.

Fail Action
This is a critical operational fault. The ABS is disabled and the ABS warning lamp is turned on. A rehome is commanded to ensure that the motors are in the home position. Two separate wheel speed = 0 codes are set if the following conditions are met:
- Two wheel speeds are 0 mph for greater than 20 seconds.
- The remaining wheel speeds are greater than 10 mph and within 7 mph.

Test Description
The number(s) below refer to step(s) on the diagnostic table.
1. This test verifies whether the malfunction is currently present.
2. This step will identify a wheel speed sensor or circuitry that is damaged and visibly apparent.
3. This test checks the wheel speed sensor for the proper resistance values.
6. This test ensures the wheel speed sensor and the sensor ring generate the proper voltage.
7. This step ensures the wheel speed sensor is not shorted to ground.
8. This step checks for proper voltages at the speed sensor harness connector.
9. This test ensures that the wheel speed sensor circuitry is not internally shorted.
21. This checks for an open in circuit BRN.
23. This checks for a short to ground in both wheel speed signal circuits.
25. This step ensures that DTC A022 was not set due to a poor connection between the EBCM and the EBCM harness connector J1.
31. This checks for an open in circuit DK GRN.

Diagnostic Aids
An intermittent malfunction may be caused by a poor connection, wire insulation that has been rubbed through, or a wire that is broken inside the insulation.
The frequency of the malfunction can be checked by using the enhanced diagnostic function of the scan tool as described in "Scan Tool Diagnostics." Scan Tool Diagnostics
If the customer's comments reflect that the ABS indicator is on only during moist environmental changes (rain, snow, vehicle wash, etc.), all wheel speed sensor circuitry should be thoroughly inspected for signs of water intrusion. Use the following procedure:
1. Spray down the suspected area with a 5 percent salt water solution (10 ml [2 teaspoons] of salt to 355 ml [12 fluid ounces] of water).
2. Start the vehicle and allow it to run for 10 seconds.
3. If the DTC returns immediately, replace the suspected harness.
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 measuring wheel speed sensor resistance, ensure that the vehicle is at room temperature (approximately 20°C [68°F]). Wheel speed sensor resistance will vary with temperature.
When replacing a wheel speed sensor, inspect the sensor terminals and the harness connector for corrosion and/or water intrusion. If evidence of corrosion or water intrusion exists, replace the wheel speed sensor and the jumper harness as necessary.

Important: Wheel speed sensor intermittent malfunctions may be difficult to locate. Take care not to disturb any electrical connections prior to an indicated step of this chart. This will insure that an intermittent connection will not be corrected before the source of the malfunction is found.











DTC A022 - Right Front Wheel Speed = 0