For 1990-2009 cars

### Circuit Description

As the wheel spins, the wheel speed sensor produces an AC signal. The electronic brake control module (EBCM) uses the frequency of the AC signal to calculate the wheel speed.

### DTC Descriptors

This diagnostic procedure supports the following DTCs:

• | DTC C0035 Left Front Wheel Speed Sensor Circuit

• | DTC C0040 Right Front Wheel Speed Sensor Circuit

• | DTC C0045 Left Rear Wheel Speed Sensor Circuit

• | DTC C0050 Right Rear Wheel Speed Sensor Circuit

This vehicle has DTCs which include DTC symptoms. For more information on DTC Symptoms--Refer to DTC Symptom Description.

DTC Symptom | DTC Symptom Descriptor
--- | ---
18 | Signal amplitude less than minimum
0F | Signal is unsteady
00 | No additional information

### Conditions for Running the DTC

#### C0035 - C0050 00 and 0F

• | The ignition switch is turned ON.

• | The ignition voltage is greater than 8 volts.

#### C0035 - C0050 18

• | The ignition switch is turned ON.

• | The ignition voltage is greater than 8 volts.

• | The brake pedal is not applied.

• | The ABS is not active.

### Conditions for Setting the DTC

#### C0035 - C0050 00

One of the following conditions exists for 0.2 second:

• | A short to voltage--The wheel speed sensor signal circuit and wheel speed sensor return circuit voltages are both greater than 4.25 volts.

• | A short to ground--The wheel speed sensor signal circuit and wheel speed sensor return circuit voltages are both less than 0.75 volts.

• | An open--The wheel speed sensor signal circuit voltage is greater than 4.25 volts and wheel speed sensor return circuit voltage is less than 0.75 volts.

#### 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

All of the following conditions exists for 0.2 second:

• | The suspect wheel speed equals zero.

• | The other wheel speeds are greater than 8 km/h (5 mph).

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

### Action Taken When the DTC Sets

If equipped, the following actions occur:

• | The EBCM disables the ABS/EDC/TCS/TPM/VSES for the duration of the ignition cycle.

• | The ACC braking function is disabled.

• | The DRP does not function optimally.

• | The ABS indicator turns ON.

• | The traction control indicator turns ON.

• | The driver information center (DIC) displays the Service Stability System message.

### Conditions for Clearing the DTC

• | The condition for 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

#### C0035 - C0050 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 (9.9 ml) of salt to 354 ml (12 oz) 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.

#### C0035 - C0050 0F

A possible cause of this DTC is electrical noise on the wheel speed sensor harness wiring. Electrical noise could result from the wheel speed sensor wires being routed to close to high energy ignition system components, such as spark plug wires.

#### C0035 - C0050 18

The following conditions may cause DTC to occur:

• | The 2 suspect wheel speeds equal to zero in 60 seconds.

• | The other wheels speeds are greater than 16 km/h (10 mph).

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

Diagnose each wheel speed sensor individually.

### Test Description

The numbers below refer to the step numbers on the diagnostic table.

1. Measure the resistance of the wheel speed sensor in order to determine if the sensor has a valid resistance value.

2. Ensures that the wheel speed sensor is generating a valid A/C voltage output.

Step | Action | Values | Yes | No
--- | --- | --- | --- | ---
Schematic Reference: Antilock Brake System Schematics Connector End View Reference: Antilock Brake System Connector End Views
1 | Did you perform the Diagnostic System Check - Vehicle? | -- | Go to Step 2 | Go to Diagnostic System Check - Vehicle
2 |

1. Install a scan tool.
2. Turn ON the ignition.
3. Set up the scan tool snap shot feature to trigger for this DTC.
4. Drive the vehicle at a speed greater than the specified value.

Does the scan tool indicate that this wheel speed DTC set?

8 km/h (5 mph)

Go to Step 3

Go to Diagnostic Aids

3 |

1. Raise and support the vehicle. Refer to Lifting and Jacking the Vehicle .
2. Disconnect the wheel speed sensor connector.
3. Measure the resistance across the wheel speed sensor.

Does the resistance measure within the specified range?

850-1350 Ω

Go to Step 4

Go to Step 8

4 |

1. Spin the wheel.
2. Measure the AC voltage across the wheel speed sensor.

Does the AC voltage measure greater than the specified value?

100 mV

Go to Step 5

Go to Step 8

5 | Inspect for poor connections at the harness connector of the wheel speed sensor. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs . Did you find and correct the condition? | -- | Go to Step 10 | Go to Step 6
6 | Test the wheel speed sensor circuits of the electronic brake control module (EBCM) for the following conditions:

• | Open

• | Short to Ground

• | Short to Voltage

• | Shorted between the Circuits

Refer to Circuit Testing and Wiring Repairs .

Did you find and correct the condition?

--

Go to Step 10

Go to Step 7

7 | Inspect for poor connections at the harness connector for the EBCM. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs . Did you find and correct the condition? | -- | Go to Step 10 | Go to Step 9
8 | Replace the wheel speed sensor (WSS). Refer to Front Wheel Bearing and Hub Replacement or Rear Wheel Bearing and Hub Replacement . Did you complete the replacement? | -- | Go to Step 10 | --
9 | Replace the EBCM. Refer to Control Module References for replacement, setup, and programming. Did you complete the replacement? | -- | Go to Step 10 | --
10 |

1. Use the scan tool in order to clear the DTCs.
2. Operate the vehicle within the Conditions for Running the DTC as specified in the supporting text.

Does the DTC reset?

--

Go to Step 2

System OK