Diagnostic Instructions

DTC Descriptors

DTC C0035 00 : Front Left Wheel Speed Sensor Malfunction

DTC C0035 5A: Front Left Wheel Speed Sensor Plausibility Error

DTC C0040 00 : Front Right Wheel Speed Sensor Malfunction

DTC C0040 5A: Front Right Wheel Speed Sensor Plausibility Error

Diagnostic Fault Information

Circuit	Short to Ground	Open/High Resistance	Short to Voltage	Signal Performance
Left Front Sensor Signal Circuit	C0035 00	C0035 00	C0035 00	C0035 5A
Left Front Sensor Low Reference Circuit	C0035 00	C0035 00	C0035 00	C0035 5A
Right Front Sensor Signal Circuit	C0040 00	C0040 00	C0040 00	C0040 5A
Right Front Sensor Low Reference Circuit	C0040 00	C0040 00	C0040 00	C0040 5A

Circuit/System Description

The wheel speed sensor receives a 12-volt power supply voltage from the electronic brake control module (EBCM) and provides an output signal to the EBCM. As the wheel spins, the wheel speed sensor sends the EBCM a DC square wave signal. The EBCM uses the frequency of the square wave signal to calculate the wheel speed.

Conditions for Running the DTC

C0035 00 - C0040 00

The ignition is ON.

C0035 5A- C0040 5A

Conditions for Setting the DTC

Action Taken When the DTC Sets

Conditions for Clearing the DTC

Diagnostic Aids

If 2 or more wheel speed sensors are inoperative diagnose each wheel speed sensor individually.

C0035 5A, 00 - C0040 5A, 00

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. Rinse the area thoroughly when completed.

Reference Information

Schematic Reference

Antilock Brake System Schematics

Connector End View Reference

Component Connector End Views

Electrical Information Reference

Scan Tool Reference

Control Module References

Circuit/System Verification

With the scan tool installed drive the vehicle in a straight line at a speed greater than 8 km/h (5 mph), all wheel speed sensors should read the same kilometres per hour.

Circuit/System Testing

Note: It is recommend that Component Testing is performed before Circuit Testing when diagnosing wheel speed sensors.

Note: Performing Circuit Testing with EBCM connector disconnected and key on will cause U codes to set. Clear DTCs after performing the test.

1. Ignition OFF, disconnect the EBCM connector. Ignition ON, measure for 0 volts between the wheel speed sensor signal circuit or the wheel speed sensor low reference circuit and ground at the EBCM connector.

⇒	If over 0 volt, repair short to voltage in the wheel speed sensor signal circuit or the wheel speed sensor supply voltage circuit.

2. Ignition OFF, disconnect the wheel speed sensor harness, measure for infinite ohms of resistance between ground and the wheel speed sensor signal and the wheel speed sensor low reference circuit from the EBCM connector.

⇒	If less than infinite ohms, repair short to ground in the sensor signal or the low reference circuit.

3. Measure for infinite ohms of resistance between the wheel speed sensor signal circuit and the wheel speed low reference circuit at the EBCM connector.

⇒	If less than infinite ohms, repair short between the wheel speed sensor signal circuit and the wheel speed sensor low reference circuit.

⇒	If all circuits test normal replace the suspect wheel speed sensor.

Component Testing

1. Ignition OFF, disconnect the wheel speed sensor connector. Connect a 12 volt test light from B+ to the positive side of the wheel speed sensor connect terminal, and the other wheel speed connector terminal to a DMM positive lead and the other lead to ground. The DMM is set on the mA display.

⇒	If the reading is below 4 mA replace the wheel speed sensor.

2. At the wheel speed sensor, set-up a DMM to measure current flow (mA/A). Spin the wheel very slowly. Measure for 4-8 mA on the low reading and 12-16 mA on the high reading.

⇒	If the low amperage output of the wheel speed sensor signal circuit is below 4 mA or above 8 mA replace the wheel speed sensor.

⇒	If the high amperage output of the wheel speed sensor signal circuit is below 12 mA or above 16 mA replace the wheel speed sensor.

Repair Instructions