Diagnostic Instructions

DTC Descriptors

DTC C0035: Left Front Wheel Speed Sensor Circuit

DTC C0040: Right Front Wheel Speed Sensor Circuit

DTC C0045: Left Rear Wheel Speed Sensor Circuit

DTC C0050: Right Rear Wheel Speed Sensor Circuit

Diagnostic Fault Information

Circuit	Short to Ground	Open/High Resistance	Short to Voltage	Signal Performance
Left Front Wheel Speed Sensor 12 Volt Reference	C0035	C0035	C0035	C0035
Left Front Wheel Speed Sensor Signal	C0035	C0035	C0035	C0035
Right Front Wheel Speed Sensor 12 Volt Reference	C0040	C0040	C0040	C0040
Right Front Wheel Speed Sensor Signal	C0040	C0040	C0040	C0040
Left Rear Wheel Speed Sensor 12 Volt Reference	C0045	C0045	C0045	C0045
Left Rear Wheel Speed Sensor Signal	C0045	C0045	C0045	C0045
Right Rear Wheel Speed Sensor 12 Volt Reference	C0050	C0050	C0050	C0050
Right Rear Wheel Speed Sensor Signal	C0050	C0050	C0050	C0050

Component	Condition	DTCs
Left Front Wheel Speed Sensor	•  Physical damage     •  Debris on the wheel speed sensor or the encoder ring     •  Loose or improperly mounted sensor     •  Loose or worn wheel bearing     •  Air gap between the wheel speed sensor and the encoder ring too large	C0035
Right Front Wheel Speed Sensor	•  Physical damage     •  Debris on the wheel speed sensor or the encoder ring     •  Loose or improperly mounted sensor     •  Loose or worn wheel bearing     •  Air gap between the wheel speed sensor and the encoder ring too large	C0040
Left Rear Wheel Speed Sensor	•  Physical damage     •  Debris on the wheel speed sensor or the encoder ring     •  Loose or improperly mounted sensor     •  Loose or worn wheel bearing     •  Air gap between the wheel speed sensor and the encoder ring too large	C0045
Right Rear Wheel Speed Sensor	•  Physical damage     •  Debris on the wheel speed sensor or the encoder ring     •  Loose or improperly mounted sensor     •  Loose or worn wheel bearing     •  Air gap between the wheel speed sensor and the encoder ring too large	C0050

Circuit/System Description

The wheel speed sensor receives 12 volts from the electronic brake control module (EBCM) and provides a DC square wave signal back to the module. As the wheel spins, the EBCM uses the frequency of the square wave signal to calculate the wheel speed.

Conditions for Running the DTC

Conditions for Setting the DTC

Action Taken When the DTC Sets

Conditions for Clearing the DTC

Diagnostic Aids

If the customer comments that the ABS indicator is ON only during moist environmental conditions: rain, snow, vehicle wash, etc., inspect the wheel speed sensor wiring for signs of water intrusion. If the DTC is not current, clear all DTCs and simulate the effects of water intrusion by using the following procedure:

1. Spray the suspected area with a 5 percent saltwater solution. To create a 5 percent saltwater solution, add 2 teaspoons of salt to 8 fl oz of water (10 g of salt to 200 ml of water).
2. Test drive the vehicle over various road surfaces, bumps, turns, etc., above 40 km/h (25 mph) for at least 30 seconds.
3. If the DTC returns, replace the suspected wheel speed sensor or repair the wheel speed sensor wiring.
4. Rinse the area thoroughly when completed.

Reference Information

Schematic Reference

Antilock Brake System Schematics

Connector End View Reference

Component Connector End Views

Description and Operation

ABS Description and Operation

Electrical Information Reference

Scan Tool Reference

Control Module References for scan tool information

Circuit/System Verification

Observe the scan tool Wheel Speed Sensor parameter. The reading should be the same speed on all sensors when driving in a straight line at a speed greater than 20 km/h (13 mph).

Circuit/System Testing

1. Ignition OFF, disconnect the X2 harness connector at the EBCM.
2. Ignition ON, test for less than 1 volt between the 12 volt reference circuit terminal of the appropriate sensor listed below and ground.

•	LF Sensor circuit terminal 18

•	RF Sensor circuit terminal 3

•	LR Sensor circuit terminal 20

•	RR Sensor circuit terminal 5

⇒	If greater than the specified range, test the 12 volt reference circuit for a short to voltage.

3. Test for less than 1 volt between the signal circuit terminal of the appropriate sensor listed below and ground.

•	LF Sensor circuit terminal 4

•	RF Sensor circuit terminal 17

•	LR Sensor circuit terminal 6

•	RR Sensor circuit terminal 19

⇒	If greater than the specified range, test the signal circuit for a short to voltage.

4. Ignition OFF, test for infinite resistance between the 12 volt reference terminal of the appropriate sensor circuit listed below and ground.

•	LF Sensor circuit terminal 18

•	RF Sensor circuit terminal 3

•	LR Sensor circuit terminal 20

•	RR Sensor circuit terminal 5

⇒	If less than the specified value, test the 12 volt reference circuit for a short to ground.

5. Test for infinite resistance between the following signal circuit terminal of the appropriate sensor circuit listed below and ground.

•	LF Sensor circuit terminal 4

•	RF Sensor circuit terminal 17

•	LR Sensor circuit terminal 6

•	RR Sensor circuit terminal 19

⇒	If less than the specified value, test the signal circuit for a short to ground.

6. Ignition OFF, disconnect the harness connector at the appropriate WSS.
7. Test for less than 2 ohms between the appropriate 12 volt reference circuit terminals listed below.

•	LF Sensor circuit terminal 18 at the EBCM harness connector, and terminal B at the WSS harness connector

•	RF Sensor circuit terminal 3 at the EBCM harness connector, and terminal B at the WSS harness connector

•	LR Sensor circuit terminal 20 at the EBCM harness connector, and terminal B at the WSS harness connector

•	RR Sensor circuit terminal 5 at the EBCM harness connector, and terminal B at the WSS harness connector

⇒	If greater than the specified range, test the 12 volt reference circuit for an open or high resistance.

8. Test for less than 2 ohms between the appropriate signal circuit terminals listed below.

•	LF Sensor circuit terminal 4 at the EBCM harness connector, and terminal A at the WSS harness connector

•	RF Sensor circuit terminal 17 at the EBCM harness connector, and terminal A at the WSS harness connector

•	LR Sensor circuit terminal 6 at the EBCM harness connector, and terminal A at the WSS harness connector

•	RR Sensor circuit terminal 19 at the EBCM harness connector, and terminal A at the WSS harness connector

⇒	If greater than the specified range, test the signal circuit for an open or high resistance.

9. If all circuits test normal, replace the appropriate wheel speed sensor. If the DTC resets replace the EBCM.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.