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C0050



DTC C0045 or C0050

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 C0045 00
- Left Rear Wheel Speed Sensor Circuit

DTC C0045 0F
- Left Rear Wheel Speed Sensor Circuit Erratic

DTC C0045 03
- Left Rear Wheel Speed Sensor Circuit Voltage Below Threshold

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

DTC C0040 00
- Right Rear Wheel Speed Sensor Circuit

DTC C0040 0F
- Right Rear Wheel Speed Sensor Circuit Erratic

DTC C0040 03
- Right Rear Wheel Speed Sensor Circuit Voltage Below Threshold

DTC C0040 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


C0045 00 or C0050 00
* The ignition is ON.
* The vehicle speed is greater than 13 km/h (8 mph).
* The wheel speed sensor feedback voltage is less than 2.2 volts for more than 100 msec.



C0045 5A or C0050 5A
* The ignition is 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 circuit on the same axle.



Conditions for Setting the DTC

* An erratic signal output of the wheel speed sensor is detected.
* A short to ground, open/high resistance is detected on the wheel speed sensor signal circuit.
* A short to voltage, short to ground or an open/high resistance is detected on the low reference circuit.
* Wheel speed sensor power supply is less than 7.6 volts.
* A missing wheel speed sensor signal
* Wheel speed sensor not mounted correctly.
* Wheel speed sensor tone ring tooth or teeth missing.
* Electro-magnetic interference (EMI).
* Defective wire harness to wheel speed sensor



Action Taken When the DTC Sets

* The EBCM disables the Antilock Brake System (ABS)/Traction Control System (TCS)/Vehicle Stability Enhancement System (VSES) for the duration of the ignition cycle.
* The electronic brake distribution (EBD) does not function optimally.
* The ABS indicator turns ON.
* The Traction Control indicator turns ON.
* 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

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 50 km/h (31 mph) for at least 20 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.



Reference Information
Schematic Reference

Antilock Brake System Schematics ([1][2]Antilock Brakes / Traction Control Systems)
Connector End View Reference

Component Connector End Views
Description and Operation

ABS Description and Operation (w/JL4) (ABS Description and Operation (With RPO JL4))ABS Description and Operation (without JL4) (ABS Description and Operation (Without RPO JL4))
Electrical Information Reference

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

Scan Tool Reference

Control Module References for Scan Tool Information


Circuit/System Verification

Ignition ON, 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 13 km/h (8 mph).


Circuit/System Testing

Important: It is recommended that Component Testing is performed before Circuit Testing when diagnosing wheel speed sensors because the module will default and does not supply voltage to the sensor when the DTC is set.


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 harness connector at the EBCM.
2. Ignition ON, test for 0 volts between the low reference circuit terminals of the appropriate sensor listed below and ground .

* LR Sensor circuit terminal B
* RR Sensor circuit terminal B


• If not the specified value, test the low reference circuit for a short to voltage. If the circuit tests normal, replace the EBCM.

3. Test for 0 volts between the signal circuit terminals of the appropriate sensor listed below and ground.

* LR Sensor circuit terminal A
* RR Sensor circuit terminal A


• If not the specified value, test the signal circuit for a short to voltage. If the circuit tests normal, replace the EBCM.

4. Ignition OFF, test for infinite resistance between the low reference terminals of the appropriate sensor listed below and ground.

* LR Sensor circuit terminal B
* RR Sensor circuit terminal B


• If not the specified value, test the low reference circuit for a short to ground. If the circuit tests normal, test or replace the wheel speed sensor.

5. Test for infinite resistance between the following signal circuit terminals of the appropriate sensor listed below and ground.

* LR Sensor circuit terminal A
* RR Sensor circuit terminal A


• If not the specified value, test the signal circuit for a short to ground. If the circuit tests normal, test or replace the wheel speed sensor.

6. If all circuits test normal, replace the EBCM.



Component Testing

1. Ignition OFF, disconnect the harness connector at the wheel speed sensor .
2. Connect a test lamp between B+ and the wheel speed sensor signal circuit terminal A.
3. Test for 4-8 mA on the low reading between the low reference terminal A and ground when spinning the wheel very slow.

• If not within the specified range, replace the wheel speed sensor.

4. Test for 12-16 mA on the high reading between the low reference terminal A and ground when spinning the wheel very slow.

• If not within the specified range, replace the wheel speed sensor.




Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

* Rear Wheel Speed Sensor Replacement (10.5 Axle) (Service and Repair)
* Control Module References for EBCM replacement, setup, and programming-Following the EBCM replacement perform the Yaw Rate Reference Table Resetting (Programming and Relearning) .


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