For 1990-2009 cars

### Diagnostic Instructions

• | Perform the Diagnostic System Check - Vehicle prior to using the 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 Malfunction
DTC C0035 0F : Left Front Wheel Speed Sensor Circuit Erratic
DTC C0035 18 : Left Front Wheel Speed Sensor Circuit Signal Amplitude Less Than Minimum
DTC C0040 00 : Right Front Wheel Speed Sensor Circuit Malfunction
DTC C0040 0F : Right Front Wheel Speed Sensor Circuit Erratic
DTC C0040 18 : Right Front Wheel Speed Sensor Circuit Signal Amplitude Less Than Minimum
DTC C0045 00 : Left Rear Wheel Speed Sensor Circuit Malfunction
DTC C0045 0F : Left Rear Wheel Speed Sensor Circuit Erratic
DTC C0045 18 : Left Rear Wheel Speed Sensor Circuit Signal Amplitude Less Than Minimum
DTC C0050 00 : Right Rear Wheel Speed Sensor Circuit Malfunction
DTC C0050 0F : Right Rear Wheel Speed Sensor Circuit Erratic
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 produces an alternating current signal whose amplitude and frequency vary, depending on the velocity of the wheel. The electronic brake control module (EBCM) uses the frequency of the AC signal to calculate the wheel speed.

### Conditions for Running the DTC

The ignition is ON.

### Conditions for Setting the DTC

• | 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.

• | One wheel speed equals 0 km/h (0 mph) while other wheel speeds are greater than 40 km/h (25 mph).

### Action Taken When the DTC Sets

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

• | ABS indicator turns ON.

### Conditions for Clearing the 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.

### 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.
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

#### 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 V 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 volts 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.

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

### Component Testing

1. Disconnect the wheel speed sensor connector. Measure for the resistance across the WSS connector terminals, resistance should be above 1M ohms.

⇒ | If the resistance is below 1M ohms, replace the WSS.

2. 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. Measure for 4-8 mA on the low reading and 12-16 mA on the high reading.

⇒ | 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