C0035-C0050 or C1221-C1228

DTC C0035-C0050 or C1221-C1228

Diagnostic Instructions

* Perform theDiagnostic System Check - Vehicle (Initial Inspection and Diagnostic Overview) prior to using this diagnostic procedure.
* ReviewStrategy Based Diagnosis (Initial Inspection and Diagnostic Overview) for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions (Initial Inspection and Diagnostic Overview)provides an overview of each diagnostic category.



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

DTC C1221 00
- Left Front Wheel Speed Sensor Circuit (HP7)

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

DTC C1225 00
- Left Front Wheel Speed Sensor Circuit Range/Performance (HP7)

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

DTC C0040 00
- Right Front Wheel Speed Sensor Circuit

DTC C1222 00
- Right Front Wheel Speed Sensor Circuit (HP7)

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

DTC C1226 00
- Right Front Wheel Speed Sensor Circuit Range/Performance (HP7)

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

DTC C0045 00
- Left Rear Wheel Speed Sensor Circuit

DTC C1223 00
- Left Rear Wheel Speed Sensor Circuit (HP7)

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

DTC C1227 00
- Left Rear Wheel Speed Sensor Circuit Range/Performance (HP7)

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

DTC C0050 00
- Right Rear Wheel Speed Sensor Circuit

DTC C1224 00
- Right Rear Wheel Speed Sensor Circuit (HP7)

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

DTC C1228 00
- Right Rear Wheel Speed Sensor Circuit Range/Performance (HP7)

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




Diagnostic Fault Information






Circuit/System Description

The wheel speed sensor receives B+ from the electronic brake control module (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.


With RPO (HP7), when a wheel speed sensor fault is detected, the EBCM sends a serial data message to the engine control module (ECM), and the ECM sets a DTC and illuminates the MIL.


Conditions for Running the DTC

C0035 00-C0050 00 or C1221 00-C1224 00

Ignition ON.


C0035 0F-C0050 0F or C1225 00-C1228 00
* Ignition ON.
* The brake pedal is not pressed.
* A DTC is not set for the other wheel speed circuit on the same axle.



C0035 18-C0050 18
* Ignition ON.
* 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.



Conditions for Setting the DTC

C0035 00-C0050 00 or C1221 00-C1224 00

The EBCM detects an open or a short to ground or a short to B+ on the wheel speed sensor signal circuits.

C0035 0F-C0050 0F or C1221 00-C1228 00

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 18-C0050 18 or C1221 00-C1224 00

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.



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 EBCM sends a serial data message to illuminate the appropriate indicator and message.



Diagnostic Aids

C0035 18-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.



Reference Information
Schematic Reference

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

Component Connector End Views (Connector Views)
Description and Operation

ABS Description and Operation (Description and Operation)
Electrical Information Reference

* Circuit Testing (Component Tests and General Diagnostics)
* Connector Repairs (Component Tests and General Diagnostics)
* Testing for Intermittent Conditions and Poor Connections (Component Tests and General Diagnostics)
* Wiring Repairs (Component Tests and General Diagnostics)

Scan Tool Reference

Control Module References (Programming and Relearning)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

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



1. Ignition OFF, disconnect the harness connector at the EBCM.
2. Ignition ON, test for less than 1 volt between the low reference circuit terminal of the appropriate sensor listed below and ground.

* LF Sensor circuit terminal 45
* RF Sensor circuit terminal 34
* LR Sensor circuit terminal 36
* RR Sensor circuit terminal 43


• If greater than the specified value, test the low reference circuit for a short to voltage. If the circuit tests normal, test or replace the wheel speed sensor.

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

* LF Sensor circuit terminal 46
* RF Sensor circuit terminal 33
* LR Sensor circuit terminal 37
* RR Sensor circuit terminal 42


• If greater than the specified value, test the signal circuit for a short to voltage. If the circuit tests normal, test or replace the wheel speed sensor.

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

* LF Sensor circuit terminal 45
* RF Sensor circuit terminal 34
* LR Sensor circuit terminal 36
* RR Sensor circuit terminal 43


• If less than 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 terminal of the appropriate sensor listed below and ground.

* LF Sensor circuit terminal 46
* RF Sensor circuit terminal 33
* LR Sensor circuit terminal 37
* RR Sensor circuit terminal 42


• If less than 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. Ignition OFF, disconnect the harness connector at the appropriate wheel speed sensor.
7. Test for less than 2 ohms between the appropriate low reference circuit terminals listed below:

* LF sensor circuit terminal 45 at the EBCM harness connector and terminal B at the WSS harness connector
* RF sensor circuit terminal 34 at the EBCM harness connector and terminal B at the WSS harness connector
* LR sensor circuit terminal 36 at the EBCM harness connector and terminal B at the WSS harness connector
* RR sensor circuit terminal 43 at the EBCM harness connector and terminal B at the WSS harness connector


• If greater than the specified value, test the low reference circuit for an open or high resistance. If the circuit tests normal, test or replace the wheel speed sensor.

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

* LF sensor circuit terminal 46 at the EBCM harness connector and terminal A at the WSS harness connector
* RF sensor circuit terminal 33 at the EBCM harness connector and terminal A at the WSS harness connector
* LR sensor circuit terminal 37 at the EBCM harness connector and terminal A at the WSS harness connector
* RR sensor circuit terminal 42 at the EBCM harness connector and terminal A at the WSS harness connector


• If greater than the specified value, test the signal circuit for an open or high resistance. If the circuit tests normal, test or replace the wheel speed sensor.

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



Repair Instructions

Perform theDiagnostic Repair Verification (Verification Tests) after completing the diagnostic procedure.

* Front Wheel Bearing and Hub Replacement (Front Suspension)
* Rear Wheel Bearing and Hub Replacement (Rear Suspension)
* Control Module References (Programming and Relearning)for EBCM replacement, setup, and programming