For 1990-2009 cars

### 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 C0035 00 : Left Front Wheel Speed Sensor Circuit No Additional Information
DTC C0035 0F : Left Front Wheel Speed Sensor Circuit Erratic Signal
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 C0040 0F : Right Front Wheel Speed Sensor Circuit Erratic Signal
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 C0045 0F : Left Rear Wheel Speed Sensor Circuit Erratic Signal
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 C0050 0F : Right Rear Wheel Speed Sensor Circuit Erratic Signal
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 | C0035 00 | C0035 00 | C0035 0F, 18
Left Front Sensor Low Reference | C0035 00 | C0035 00 | C0035 00 | C0035 0F, 18
Right Front Sensor Signal | C0040 00 | C0040 00 | C0040 00 | C0040 0F, 18
Right Front Sensor Low Reference | C0040 00 | C0040 00 | C0040 00 | C0040 0F, 18
Left Rear Sensor Signal | C0045 00 | C0045 00 | C0045 00 | C0045 0F, 18
Left Rear Sensor Low Reference | C0045 00 | C0045 00 | C0045 00 | C0045 0F, 18
Right Rear Sensor Signal | C0050 00 | C0050 00 | C0050 00 | C0050 0F, 18
Right Rear Sensor Low Reference | C0050 00 | C0050 00 | C0050 00 | C0050 0F, 18

### Circuit/System Description

The wheel speed sensor receives a 12-volt power supply voltage from the electronic brake control module (EBCM) and provides an output signal to the 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.

### Conditions for Running the DTC

#### C0035-C0050 00

• | The ignition is ON.

• | Ignition voltage is greater than 9.5 volts.

#### C0035-C0050 0F

• | 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.

#### C0035-C0050 18

• | The ignition is ON.

• | Ignition voltage is greater than 9.5 volts.

• | The brake pedal is not pressed.

• | No other wheel speed circuit DTCs are set.

• | At least 2 other wheel speeds are not 0 km/h.

### Conditions for Setting the DTC

#### C0035-C0050 00

• | An open is detected on the wheel speed sensor signal circuit.

• | A short to ground is detected on the wheel speed sensor signal circuit.

• | A short to voltage is detected on the wheel speed sensor signal circuit.

#### C0035-C0050 0F

The EBCM detects a rapid variation in the wheel speed. The wheel speed changes by 20 km/h (12 mph) or more in 0.01 second. The change must occur 3 times with no more than 0.2 second between occurrences.

#### C0035-C0050 18

• | One wheel speed is 2 km/h (1.2 mph) .

• | The remaining wheel speeds are greater than 10 km/h (6.2 mph).

• | The difference between the remaining wheel speeds is less than 8 km/h (5 mph) from each other for 180 seconds.

OR

• | The 2 wheel speed sensor inputs are 0 and DTCs are set.

• | The 2 suspect wheel speeds equal zero for 6 seconds.

• | The other wheel speeds are greater than 15 km/h (10 mph).

• | The other wheel speeds are within 11 km/h (7 mph) of each other.

### Action Taken When the DTC Sets

• | The EBCM disables the Antilock Brake System (ABS) Control System for the duration of the ignition cycle.

• | ABS indicator turns ON.

• | Driver information center (DIC) displays the ABS FAULT message.

• | If both rear wheel speed DTCs are set, the dynamic rear proportioning (DRP) is disabled and the Brake Warning indicator turns ON.

### Conditions for Clearing the MIL/DTC

• | The condition for setting the DTC is no longer present and the DTC is cleared with a scan tool.

• | The EBCM automatically clears the history DTC when a current DTC is not detected in 100 consecutive drive cycles.

• | The ABS telltale will remain on until a vehicle speed of 13 km/h (8 mph) or greater is achieved, unless the scan tool is used to clear the DTC.

### 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 40 km/h (25 mph) for at least 30 seconds. Also rotate steering wheel from stop to stop for intermittent condition caused from open or chaffing of the front wheel speed sensor harness.
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 Reference

ABS Description and Operation

#### Electrical Information Reference

• | Circuit Testing

• | Testing for Intermittent Conditions and Poor Connections

• | Wiring Repairs

• | Connector Repairs

#### Scan Tool Reference

Scan Tool Data List

### Circuit/System Verification

With scan tool installed drive the vehicle in a straight line at a speed greater than 10 km/h (6 mph), all wheel speed sensors should read the same speed.

### Circuit/System Testing

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

Important: Performing Circuit Testing with EBCM connector disconnected and key on will cause U codes to set. Clear DTCs after performing the test.

1. With the ignition OFF, disconnect the wheel speed sensor connector. Ignition ON, measure for voltage above 7.5 V on the wheel speed sensor signal circuit.

⇒ | If voltage is below 7.5 check for a short to ground, open or replace EBCM.

2. Ignition OFF, disconnect the EBCM connector. With the EBCM connector disconnected and the ignition ON, measure for 0 volt between the wheel speed sensor signal circuit or the wheel speed sensor low reference circuit and ground at the EBCM connector.

⇒ | If over 0 volts, repair short to voltage in the wheel speed sensor signal circuit or the wheel speed sensor supply voltage circuit.

3. With the ignition OFF and the wheel speed sensor harness disconnected, measure for infinite ohms of resistance between ground and the wheel speed sensor signal and the wheel speed sensor low reference circuit from the EBCM connector.

⇒ | If less than infinite ohms, repair short to ground in the sensor signal or the low reference circuit.

4. Measure for infinite ohms of resistance between the wheel speed sensor signal circuit and the wheel speed low reference circuit at the EBCM connector.

⇒ | If less than infinite ohms, repair short between the wheel speed sensor signal circuit and the wheel speed sensor low reference circuit.

5. If all circuits test normal replace the suspect wheel speed sensor.

### Component Testing

1. Ignition OFF, disconnect the wheel speed sensor connector. Measure for 12 volts on the wheel speed sensor signal circuit.
2. Measure for 12 volts on the wheel speed sensor signal circuit.

⇒ | If the voltage is below 7.5 check for a short to ground, open or replace EBCM.

3. At the wheel speed sensor, connect a 3A fused jumper wire between wheel speed sensor low reference terminal and the low reference terminal of the wheel speed harness connector. Set-up a DMM to measure current flow (mA/A). Connect the positive terminal of the DMM to the wheel speed sensor signal terminal at the wheel speed sensor harness connector and the negative lead to the wheel speed sensor signal terminal of the wheel speed sensor. Spin the wheel very slowly, the amperage should fall and rise between 4 mA and 16 mA . Measure the low and the high readings.

⇒ | If the low amperage output of the wheel speed sensor signal circuit is below 4 mA or above 8 mA replace the wheel speed sensor.

⇒ | If the high amperage output of the wheel speed sensor signal circuit is below 12 mA or above 16 mA replace the wheel speed sensor.

### Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

Control Module References for EBCM and BPMV replacement, setup, and programming