Diagnostic Instructions

DTC Descriptors

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

DTC C0035 00: Left Front Wheel Speed Sensor Circuit

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

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

DTC C0040 00: Right Front Wheel Speed Sensor Circuit

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

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

DTC C0045 00: Left Rear Wheel Speed Sensor Circuit

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

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

DTC C0050 00: Right Rear Wheel Speed Sensor Circuit

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

DTC C1221: Left Front Wheel Speed Sensor Circuit

DTC C1222: Right Front Wheel Speed Sensor Circuit

DTC C1223: Left Rear Wheel Speed Sensor Circuit

DTC C1224: Right Rear Wheel Speed Sensor Circuit

DTC C1225: Left Front Wheel Speed Sensor Circuit Range/Performance

DTC C1226: Right Front Wheel Speed Sensor Circuit Range/Performance

DTC C1227: Left Rear Wheel Speed Sensor Circuit Range/Performance

DTC C1228: Right Rear Wheel Speed Sensor Circuit Range/Performance

Diagnostic Fault Information

Circuit	Short to Ground	Open/High Resistance	Short to Voltage	Signal Performance
Left Front Sensor Signal	C0035 00, C1221	C0035 00, C1221	C0035 00, C1221	C0035 0F 18, C1225
Left Front Sensor Low Reference	C0035 00, C1221	C0035 00, C1221	C0035 00, C1221	C0035 0F 18, C1225
Right Front Sensor Signal	C0040 00, C1222	C0040 00, C1222	C0040 00, C1222	C0040 0F 18, C1226
Right Front Sensor Low Reference	C0040 00, C1222	C0040 00, C1222	C0040 00, C1222	C0040 0F 18, C1226
Left Rear Sensor Signal	C0045 00, C1223	C0045 00, C1223	C0045 00, C1223	C0045 0F 18, C1227
Left Rear Sensor Low Reference	C0045 00, C1223	C0045 00, C1223	C0045 00, C1223	C0045 0F 18, C1227
Right Rear Sensor Signal	C0050 00, C1224	C0050 00, C1224	C0050 00, C1224	C0050 0F 18, C1228
Right Rear Sensor Low Reference	C0050 00, C1224	C0050 00, C1224	C0050 00, C1224	C0050 0F 18, C1228

Circuit/System Description

The wheel speed sensor (WSS) 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. The ECM may set a related chassis DTC as a result of OBD 2 emission requirements. The ECM chassis DTC's are used to illuminate the emission light when necessary and to indicate faults within the EBCM subsystems.

Conditions for Running the DTC

C0035-C0050 18

C0035-C0050 0F or C1225-C1228

C0035-C0050 00 or C1221-C1224

Conditions for Setting the DTC

C0035-C0050 18

C0035-C0050 0F or C1225-C1228

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 or C1221-C1224

Action Taken When the DTC Sets

If equipped, the following actions occur:

Conditions for Clearing the DTC

Diagnostic Aids

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

Connector End View Reference

Component Connector End Views

Description and Operation

ABS Description and Operation

Electrical Information Reference

Scan Tool Reference

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 volt between the ignition voltage circuit terminal of the appropriate sensor listed below and ground.

•	LF Sensor circuit terminal A1

•	RF Sensor circuit terminal A3

•	LR Sensor circuit terminal A5

•	RR Sensor circuit terminal A7

⇒	If greater than the specified range, test the ignition voltage 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 A2

•	RF Sensor circuit terminal A4

•	LR Sensor circuit terminal A6

•	RR Sensor circuit terminal A8

⇒	If greater than the specified range, test the signal circuit for a short to voltage.

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

•	LF Sensor circuit terminal A1

•	RF Sensor circuit terminal A3

•	LR Sensor circuit terminal A5

•	RR Sensor circuit terminal A7

⇒	If less than the specified value, test the ignition voltage circuit for a short to ground.

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

•	LF Sensor circuit terminal A2

•	RF Sensor circuit terminal A4

•	LR Sensor circuit terminal A6

•	RR Sensor circuit terminal A8

⇒	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. Ignition OFF, test for less than 2 ohms between the appropriate ignition voltage circuit terminals listed below.

•	LF Sensor circuit terminal A1 at the EBCM harness connector and terminal A at the WSS harness connector.

•	RF Sensor circuit terminal A3 at the EBCM harness connector and terminal A at the WSS harness connector.

•	LR Sensor circuit terminal A5 at the EBCM harness connector and terminal A at the WSS harness connector.

•	RR Sensor circuit terminal A7 at the EBCM harness connector and terminal A at the WSS harness connector.

⇒	If greater than the specified value, test the ignition voltage 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 A2 at the EBCM harness connector and terminal B at the WSS harness connector.

•	RF Sensor circuit terminal A4 at the EBCM harness connector and terminal B at the WSS harness connector.

•	LR Sensor circuit terminal A6 at the EBCM harness connector and terminal B at the WSS harness connector.

•	RR Sensor circuit terminal A8 at the EBCM harness connector and terminal B at the WSS harness connector.

⇒	If greater than the specified value, 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 after completing the diagnostic procedure.