Greater Than or Equal to 8600LB GVW

DTC C0035 or C0040 (Greater than or equal to 8600lb GVW)

Diagnostic Instructions

- Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.
- Review Strategy Based Diagnosis for an overview of the diagnostic approach.
- Diagnostic Procedure Instructions provides an overview of each diagnostic category.

DTC Descriptors

- DTC C0035 02: Left Front Wheel Speed Sensor Circuit Short to Ground.
- DTC C0035 05: Left Front Wheel Speed Sensor Circuit Short to Battery or Open.
- DTC C0035 0F: Left Front Wheel Speed Sensor Circuit Erratic.
- DTC C0035 18: Left Front Wheel Speed Sensor Circuit Signal Amplitude Below Minimum.
- DTC C0040 02: Right Front Wheel Speed Sensor Circuit Short to Ground.
- DTC C0040 05: Right Front Wheel Speed Sensor Circuit Short to Battery or Open.
- DTC C0040 0F: Right Front Wheel Speed Sensor Circuit Erratic.
- DTC C0040 18: Right Front Wheel Speed Sensor Circuit Signal Amplitude Below Minimum.

Diagnostic Fault Information









Circuit/System Description

The wheel speed sensor receives ignition voltage 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

- The ignition is ON.
- Ignition voltage is greater than 9.5 volts.

Conditions for Setting the DTC

C0035 002 or C0040 02
- A short to ground is detected on the wheel speed sensor 12-volt reference or signal circuit..

C0035 05 or C0040 05
- A short to voltage or an open/high resistance is detected on the wheel speed sensor 12-volt reference or signal circuit.

C0035 0F, C0035 18, C0040 0F or C0040 18
- An erratic signal output of the wheel speed sensor is detected.

Action Taken When the DTC Sets

- The EBCM disables the antilock brake system (ABS)/traction control system (TCS) and vehicle stability enhancement system (VSES) for the duration of the ignition cycle.
- The ABS indicator illuminates.
- The Stabilitrak indicator illuminates.
- The driver information center (DIC) displays the Service Stability System message.

Conditions for Clearing the DTC

- The condition for setting the DTC is no longer present.
- The EBCM automatically clears the history DTC when a current DTC is not detected in 100 consecutive drive cycles.

Diagnostic Aids

- Inspect the back of the wheel bearing on the encoder surface for metal debris that could cause an erratic reading with the sensor. Do not use a magnet to clean the debris, or damage to the encoder ring may occur.
- If 2 or more wheel speed sensors are inoperative diagnose each wheel speed sensor individually.
- An ECE 13 response may be required, after repairs are made, and DTCs are cleared, operate the vehicle at speeds greater than 15 km/h (10 mph) to complete the self test, and the EBCM will turn off the ABS indicator.

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.

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 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 15
- RF Sensor circuit terminal 26
-> If greater than the specified range, test the low 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 16
- RF Sensor circuit terminal 27
-> 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 15
- RF Sensor circuit terminal 26
-> 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 16
- RF Sensor circuit terminal 27
-> 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 15 at the EBCM harness connector, and terminal B at the WSS harness connector.
- RF Sensor circuit terminal 26 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 16 at the EBCM harness connector, and terminal A at the WSS harness connector.
- RF Sensor circuit terminal 27 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.