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C0038




DTC C0035-C0050 (With JL4)

Diagnostic Instructions

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

DTC Descriptors
DTC C0035 00
- Left Front Wheel Speed Sensor Circuit

DTC C0035 5A
- Left Front Wheel Speed Sensor Circuit Plausibility Failure

DTC C0040 00
- Right Front Wheel Speed Sensor Circuit

DTC C0040 5A
- Right Front Wheel Speed Sensor Circuit Plausibility Failure

DTC C0045 00
- Left Rear Wheel Speed Sensor Circuit

DTC C0045 5A
- Left Rear Wheel Speed Sensor Circuit Plausibility Failure

DTC C0050 00
- Right Rear Wheel Speed Sensor Circuit

DTC C0050 5A
- Right Rear Wheel Speed Sensor Circuit Plausibility Failure

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

C0035 00-C0050 00
* Ignition ON.
* Ignition voltage is greater than 9.5 volts.

C0035 5A-C0050 5A
* Ignition ON.
* Ignition voltage is greater than 9.5 volts.
* The brake pedal is not pressed.
* A DTC is not set for the other wheel speed sensor on the same axle.

Conditions for Setting the DTC

C0035 00-C0050 00
* A short to ground, or an open/high resistance is detected on the wheel speed sensor 12-volt reference circuit.
* A short to voltage, short to ground or an open/high resistance is detected on the signal circuit.
* Wheel speed sensor power supply is less than 7.6 volts.
* A missing wheel speed sensor signal

C0035 5A-C0050 5A

An erratic signal output of the wheel speed sensor is detected.

Actions Taken when the DTC Sets

* The EBCM disables the antilock brake system (ABS, traction control system and vehicle stability enhancement system for the duration of the ignition cycle.
* The ABS indicator illuminates.
* The StabiliTrak indicator illuminates.
* The EBCM disables the voltage to the wheel speed sensor the fault is detected on.

Conditions for Clearing the DTC

* The condition for the DTC is no longer present.
* The EBCM clears the history DTC when a current DTC is not detected in 40 consecutive drive cycles.

Note: During normal diagnostic and/or repair verification technicians may find that the ABS, Traction Control and/or Stabilitrak indicators may be ON with NO DTCs displayed by the EBCM. Do not replace the EBCM for this condition.

If the ABS, Traction Control and/or Stabilitrak telltales are ON with no DTCs set, perform the following steps:

1. Remove the key from the ignition, open and close the driver's door to turn off retained accessory power (RAP), and wait 60 seconds.
2. Ignition ON, if the ABS, Traction Control and/or Stabilitrak telltales are still illuminated, operate the vehicle at speeds greater than 15 km/h (10 mph) to complete the self test. The EBCM should request all telltale indicators to turn OFF.
3. If the telltales remain ON with no DTCs set after the drive cycle, disconnect the battery for at least 60 seconds then reconnect the battery.
4. Operate the vehicle at speeds greater than 40 km/h (25 mph), the EBCM should request all telltale indicators to turn OFF.

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.

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, 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 [1][2]Antilock Brakes / Traction Control Systems
Connector End View Reference

Component Connector End Views 1-2 Shift Solenoid (SS) Valve (M30)
Description and Operation

ABS Description and Operation ABS (Less than 3900 kg (8600 lb) GVW)
Electrical Information Reference

* Circuit Testing Circuit Testing
* Connector Repairs Connector Repairs
* Testing for Intermittent Conditions and Poor Connections Testing for Intermittent Conditions and Poor Connections
* Wiring Repairs Wiring Repairs

Scan Tool Reference

Control Module References 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 harness connector at the EBCM.
2. Ignition ON, test for less than 1 V between the 12 V reference circuit terminal of the appropriate sensor listed below and ground.

* Left Front Sensor circuit terminal 21
* Right Front Sensor circuit terminal 18
* Left Rear Sensor circuit terminal 33
* Right Rear Sensor circuit terminal 19

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

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

* Left Front Sensor circuit terminal 34
* Right Front Sensor circuit terminal 6
* Left Rear Sensor circuit terminal 20
* Right Rear Sensor circuit terminal 31

• 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 V reference terminal of the appropriate sensor circuit listed below and ground.

* Left Front Sensor circuit terminal 21
* Right Front Sensor circuit terminal 18
* Left Rear Sensor circuit terminal 33
* Right Rear Sensor circuit terminal 19

• If less than the specified value, test the 12 V 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.

* Left Front Sensor circuit terminal 34
* Right Front Sensor circuit terminal 6
* Left Rear Sensor circuit terminal 20
* Right Rear Sensor circuit terminal 31

• 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 wheel speed sensor.
7. Test for less than 2 ohm between the appropriate 12 V reference circuit terminals listed below.

* Left Front Sensor circuit terminal 21 at the EBCM harness connector, and terminal 2 at the wheel speed sensor harness connector
* Right Front Sensor circuit terminal 18 at the EBCM harness connector, and terminal 2 at the wheel speed sensor harness connector
* Left Rear Sensor circuit terminal 33 at the EBCM harness connector, and terminal B at the wheel speed sensor harness connector
* Right Rear Sensor circuit terminal 19 at the EBCM harness connector, and terminal B at the wheel speed sensor harness connector

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

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

* Left Front Sensor circuit terminal 34 at the EBCM harness connector, and terminal 1 at the wheel speed sensor harness connector
* Right Front Sensor circuit terminal 6 at the EBCM harness connector, and terminal 1 at the wheel speed sensor harness connector
* Left Rear Sensor circuit terminal 20 at the EBCM harness connector, and terminal A at the wheel speed sensor harness connector
* Right Rear Sensor circuit terminal 31 at the EBCM harness connector, and terminal A at the wheel speed sensor 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 Verification Tests after completing the diagnostic procedure.

* Front Wheel Speed Sensor Replacement Less than 3900 kg (8600 lb) GVW
* Rear Wheel Speed Sensor Replacement Less than 3900 kg (8600 lb) GVW
* Control Module References Control Module References for EBCM replacement, programming and setup

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