Diagnostic Instructions

DTC Descriptors

DTC C0035 00: Left Front Wheel Speed Sensor Circuit No Additional Information

DTC C1221: Left Front Wheel Speed Sensor Circuit

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

DTC C1225: Left Front Wheel Speed Sensor Circuit Range Performance

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

DTC C0040 00: Right Front Wheel Speed Sensor Circuit No Additional Information

DTC C1222: Right Front Wheel Speed Sensor Circuit

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

DTC C1226: Right Front Wheel Speed Sensor Circuit Range Performance

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

DTC C0045 00: Left Rear Wheel Speed Sensor Circuit No Additional Information

DTC C1223: Left Rear Wheel Speed Sensor Circuit

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

DTC C1227: Left Rear Wheel Speed Sensor Circuit Range Performance

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

DTC C0050 00: Right Rear Wheel Speed Sensor Circuit No Additional Information

DTC C1224: Right Rear Wheel Speed Sensor Circuit

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

DTC C1224: Right Rear Wheel Speed Sensor Circuit Range Performance

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

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 receives ignition 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. When the EBCM sets a wheel speed sensor DTC, the engine control module (ECM) receives a serial data message of the fault detected and ECM sets a DTC and illuminates the MIL.

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

The code is set when the following conditions exist:

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

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

Action Taken When the DTC Sets

If equipped, the following actions occur:

1. The EBCM disables the antilock brake system (ABS)/traction control system (TCS) for the duration of the ignition cycle.
2. The ABS indicator illuminates.
3. The Traction OFF indicator illuminates.
4. 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.
5. When the EBCM disables DRP, the red Brake warning indicator illuminates.

Conditions for Clearing the DTC

Diagnostic Aids

C0035 - 0050 18

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

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

Connector End View Reference

Antilock Brake System Connector End Views

Description and Operation

ABS Description and Operation

Electrical Information Reference

Scan Tool Reference

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

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 suspect wheel speed sensor.
2. Ignition ON, test for ignition voltage between the voltage circuit terminal A and ground.

⇒	If not the specified value, test the voltage circuit for a short to ground or open/high resistance. If the circuit tests normal, replace the EBCM.

3. Test for ignition voltage between the voltage circuit terminal A and the signal circuit terminal B.

⇒	If not the specified value, test the signal circuit for an open/high resistance. If the circuit tests normal, replace the EBCM.

4. Disconnect the harness connector at the EBCM.
5. Test for infinite resistance between the signal circuit terminal B and ground.

⇒	If not the specified value, test the signal circuit for a short to ground.

6. If all circuits test normal, test or replace the wheel speed sensor.

Component Testing

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

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

4. Test for 11-16 mA on the high reading between the signal terminal 2 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.