C0046

DTC C0045 / C0046: Left Rear Wheel Speed Sensor Circuit Malfunction





Circuit Description
The toothed wheel generates a voltage pulse as it moves past the sensor. Each tooth-gap-tooth series on the wheel generates the pulses. The Electronic Brake Control Module (EBCM) uses the frequency of these pulses to determine the wheel speed. The voltage generated depends on the air gap between the sensor and the toothed wheel, and on the wheel speed.

Diagnosis
This procedure checks for a malfunctioning wheel speed sensor, a short to ground or to voltage in the wiring or a contact problem in a connector.

Cause(s)
- The wheel speed sensor is defective or disconnected.
- There is a problem in the wiring.
- There is a problem with a connector.
- There is a problem in the toothed ring.
- Wrong installed WSS.
- Wrong sensor signal.
- Signal noise via WSS.

Fail Action
ABS action is disabled, and the ABS warning lamp is ON. EBD is enabled. (Refer to the EBD failure matrix)

Test Description
Number(s) below refer to the step number(s) on the Diagnostic Table.
1. This step begins an examination for a defective wheel speed sensor.
2. This step tests the wiring for a short to voltage.
3. This step tests the wiring for a short to ground.
4. This step tests for an open or a high resistance in the wiring.

Diagnostic Aids
Be sure that the speed sensor wiring is properly routed and retained. This will help to prevent false signals due to the pickup of electrical noise.
It is very important to perform a thorough inspection of the wiring and the connectors. Failure to inspect the wiring and the connectors carefully and completely may result in misdiagnosis, causing part replacement with the reappearance of the malfunction.
You can use the scan tool to monitor wheel speeds during a road test. Watch the wheel speeds being displayed on the scan tool to see if any of the readings is unusual, such as one sensor varying in speed from the other three, a signal going intermittently high or low, etc. If this does not identify the intermittent, wet the speed sensor harness on the underside of the vehicle and perform a road test, monitoring wheel speeds with the scan tool.

NOTE: If the WSS signal fault input to the EBCM, the ABS warning lamp turns ON. As if a sensor signal fault can be removed by the scan tool, the ABS warning lamp doesn't turn OFF. In order to turn ABS warning lamp OFF, you should drive a car up to 12 km/h.

Troubleshooting

Step 1-8:

Step 9-12: