C0040

DTC C0035-C0050

Circuit Description

The wheel speed sensor receives a 12-volt reference voltage from the electronic brake control module (EBCM) and a ground through the chassis of the vehicle. 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.

DTC Descriptors

This diagnostic procedure supports the following DTCs:

* DTC C0035 LF Wheel Speed Sensor Circuit
* DTC C0040 RF Wheel Speed Sensor Circuit
* DTC C0045 LR Wheel Speed Sensor Circuit
* DTC C0050 RR Wheel Speed Sensor Circuit

This vehicle has DTCs which include DTC Symptoms. For more information on DTC Symptoms, refer to DTC Symptom Description .





Conditions for Running the DTC

C0035 - C0050 18
* The ignition is ON.
* Ignition voltage is greater than 8 volts.
* The brake pedal is not pressed.
* No other wheel speed circuit DTCs are set.
* At least two other wheel speeds are not 0 km/h.

C0035 - C0050 0F
* The ignition is ON.
* Ignition voltage is greater than 8 volts.
* The brake pedal is not pressed.
* A DTC is not set for the other wheel speed circuit on the same axle.

C0035 - C0050 00
* The ignition is ON.
* Ignition voltage is greater than 8 volts.

Conditions for Setting the DTC

C0035 - C0050 18

The code is set when the following conditions exist:

* One wheel speed is 0 km/h.
* The remaining wheel speeds are greater than 8 km/h (5 mph).
* The difference between the remaining wheel speeds is less than 11 km/h (7 mph) from each other.

C0035 - C0050 0F

If the EBCM detects a change in wheel speed that exceeds 20 km/h (12 mph) between two 10 millisecond wheel speed samples. If the condition occurs 3 times in 200 milliseconds, the code is set.

C0035 - C0050 00

The code is set when either of the following conditions exist:

* An open or a short to ground is detected on the wheel speed sensor signal circuit by the EBCM.
* A short to voltage is detected on the wheel speed sensor signal circuit by the EBCM.

Action Taken When the DTC Sets

If equipped, the following actions occur:

* The EBCM disables the ABS/TCS for the duration of the ignition cycle.
* The ABS indicator turns ON.
* The Traction OFF indicator turns ON.
* If the other wheel speed sensor on the same axle sets an additional DTC, the EBCM disables the DRP for the duration of the ignition cycle.
* When the EBCM disables DRP, the red Brake warning indicator turns ON.

Diagnostic Aids

C0035 - C0050 18

Under the following conditions, 2 Wheel Speed Sensor Input is 0 and DTCs are set:

* The 2 suspect wheel speeds equal zero for 6 seconds.
* The other wheel speeds are greater than 16 km/h (10 mph).
* The other wheel speeds are within 11 km/h (7 mph) of each other.

Diagnose each wheel speed sensor individually.

C0035 - C0050 18, 0F, 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. If the DTC returns, replace the suspected wheel speed sensor or repair the wheel speed sensor wiring.
4. Rinse the area thoroughly when completed.

Test Description

The numbers below refer to the step numbers on the diagnostic table.
4. Measures the voltage of the wheel speed sensor reference voltage circuit in order to determine if the sensor is able to send a signal.
5. The EBCM can not determine a short to ground on a individual wheel speed sensor supply voltage circuits. The EBCM can only detect a short to ground on one side of the vehicle. Therefore if a short to ground is detected on a wheel speed sensor supply voltage circuit, both front and rear wheel speed sensor DTCs are set on the same side of the vehicle.
8. Ensures that the wheel speed sensor is generating a valid DC square wave output.
9. Measures the average amperage output of the wheel speed sensor signal in order to detect an erratic signal.

Step 1 - Step 7:

Step 8 - Step 13: