Diagnostic Instructions

DTC Descriptors

DTC C0035 00 : Left Front Wheel Speed Sensor Circuit No Additional Information

DTC C0035 0F : Left Front Wheel Speed Sensor Circuit Erratic Signal

DTC C0035 18 : Left Front Wheel Speed Sensor Circuit Signal Amplitude Less Than Minimum

DTC C0040 00 : Right Front Wheel Speed Sensor Circuit No Additional Information

DTC C0040 0F : Right Front Wheel Speed Sensor Circuit Erratic Signal

DTC C0040 18 : Right Front Wheel Speed Sensor Circuit Signal Amplitude Less Than Minimum

DTC C0045 00 : Left Rear Wheel Speed Sensor Circuit No Additional Information

DTC C0045 0F : Left Rear Wheel Speed Sensor Circuit Erratic Signal

DTC C0045 18 : Left Rear Wheel Speed Sensor Circuit Signal Amplitude Less Than Minimum

DTC C0050 00 : Right Rear Wheel Speed Sensor Circuit No Additional Information

DTC C0050 0F : Right Rear Wheel Speed Sensor Circuit Erratic Signal

DTC C0050 18 : Right Rear Wheel Speed Sensor Circuit Signal Amplitude Less Than Minimum

Diagnostic Fault Information

Circuit	Short to Ground	Open/High Resistance	Short to Voltage	Signal Performance
Left Front Sensor Signal	C0035 00	C0035 00	C0035 00	C0035 0F, 18
Left Front Sensor Low Reference	C0035 00	C0035 00	C0035 00	C0035 0F, 18
Right Front Sensor Signal	C0040 00	C0040 00	C0040 00	C0040 0F, 18
Right Front Sensor Low Reference	C0040 00	C0040 00	C0040 00	C0040 0F, 18
Left Rear Sensor Signal	C0045 00	C0045 00	C0045 00	C0045 0F, 18
Left Rear Sensor Low Reference	C0045 00	C0045 00	C0045 00	C0045 0F, 18
Right Rear Sensor Signal	C0050 00	C0050 00	C0050 00	C0050 0F, 18
Right Rear Sensor Low Reference	C0050 00	C0050 00	C0050 00	C0050 0F, 18

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 - C0050 00

C0035 - C0050 0F

C0035 - C0050 18

Conditions for Setting the DTC

C0035 - C0050 00

C0035 - C0050 0F

The EBCM detects a rapid variation in the wheel speed. The wheel speed changes by 20 km/h (12 mph) or more in 0.01 second. The change must occur 3 times with no more than 0.2 second between occurrences.

C0035 - C0050 18

OR

Action Taken When the DTC Sets

Conditions for Clearing the MIL/DTC

Diagnostic Aids

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

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. Also rotate steering wheel from stop to stop for intermittent condition caused from open or chaffing of the front wheel speed sensor harness.
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

Antilock Brake System Connector End Views

Description and Operation Reference

ABS Description and Operation

Electrical Information Reference

Scan Tool Reference

Scan Tool Data List

Circuit/System Verification

With scan tool installed drive the vehicle in a straight line at a speed greater than 10 km/h (6 mph), all wheel speed sensors should read the same speed.

Circuit/System Testing

Important: It is recommended that Component Testing is performed before Circuit Testing when diagnosing wheel speed sensors.

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

1. With the ignition OFF, disconnect the wheel speed sensor connector. Ignition ON, Measure for voltage above 7.5 V on the wheel speed sensor signal circuit.

⇒	If voltage is below 7.5 check for a short to ground, open or replace EBCM.

2. Ignition OFF, disconnect the EBCM connector. With the EBCM connector disconnected and the ignition ON, measure for 0 volt 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.

3. With the ignition OFF and the wheel speed sensor harness disconnected, 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.

4. 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.

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

Component Testing

1. Ignition OFF, disconnect the wheel speed sensor connector. Measure for 12 volts on the wheel speed sensor signal circuit.
2. Measure for 12 volts on the wheel speed sensor signal circuit.

⇒	If the If voltage is below 7.5 check for a short to ground, open or replace EBCM.

3. At the wheel speed sensor, connect a 3A fused jumper wire between wheel speed sensor low reference terminal and the low reference terminal of the wheel speed harness connector. Set-up a DMM to measure current flow (mA/A). Connect the positive terminal of the DMM to the wheel speed sensor signal terminal at the wheel speed sensor harness connector and the negative lead to the wheel speed sensor signal terminal of the wheel speed sensor. Spin the wheel very slowly, the amperage should fall and rise between 4 mA and 16 mA . Measure the low and the high readings.

⇒	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

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.