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.

### Conditions for Running the DTC

#### C0221, C0225, C0231 and C0235

The ignition is ON.

#### C0222, C0223, C0226, C0227, C0232, C0233, C0236 and C0237

The vehicle speed is greater than 19 km/h (12 mph).

### Conditions for Setting the DTC

#### C0221, C0225, C0231 and C0235

The corresponding wheel speed sensor feedback voltage is detected as being excessively high or low for 1 second.

#### C0222, C0226, C0232 and C0236

The corresponding wheel speed sensor signal is less than 6 km/h (4 mph) for 5 seconds, or for 120 seconds to set multiple missing sensor signal DTCs.

#### C0223, C0227, C0233 and C0237

The EBCM detects an erratic signal from the corresponding wheel speed sensor for 15 milliseconds.

### Action Taken When the DTC Sets

• | The EBCM disables the ABS.

• | The ABS indicator turns ON.

### Conditions for Clearing the DTC

The conditions for setting the DTC are no longer present and you use the scan tool Clear DTCs function.

### Diagnostic Aids

Thoroughly inspect connections or circuitry that may cause an intermittent malfunction. Refer to Testing for Intermittent Conditions and Poor Connections , Connector Repairs , Testing for Electrical Intermittents and Wiring Repairs in Wiring Systems.

If the customer's concern is that the ABS indicator is on only during humid conditions such as rain, snow or vehicle wash, thoroughly inspect the wheel speed sensor circuits for signs of water intrusion. Use the following procedure in order to help isolate the problem area:

1. Spray the suspected area with a 5 percent salt water solution: 10 grams (2 teaspoons) of salt to 200 ml (12 oz) of water.
2. Operate the vehicle at a speed greater than 19 km/h (12 mph) for at least 30 seconds.

Repair or replace the suspect harness if the DTC sets.

### Test Description

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

1. This step tests for the correct bearing play. Excessive bearing play can cause wheel speed sensor air gap to exceed specification. Wheel speed sensor air gap must be reinspected after a repair is made to correct excessive bearing play.

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

3. Ensures the wheel speed sensor is generating a valid AC voltage output.

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

1. Use the scan tool in order to clear the DTCs.
2. Operate the vehicle at a speed greater than the specified value.

Does the DTC set?

19 km/h (12 mph)

Go to Step 3

Go to Diagnostic Aids

3 |

1. Raise and support the vehicle. Refer to Lifting and Jacking the Vehicle in General Information.
2. Inspect the wheel bearings for looseness or excessive wear and verify that the wheel bearing play is within specifications. Refer to Wheel Bearing Adjustment or Front Wheel Hub, Bearing, and Seal Replacement in Front Suspension or Wheel Bearing Wear - Rear Drive Axle or Wheel Bearing Adjustment in Rear Drive Axle.

Did you find and correct the condition?

--

Go to Step 12

Go to Step 4

4 | Inspect the wheel speed sensor in order to ensure the sensor is installed and retained properly for proper air gap. Refer to Front Wheel Speed Sensor Replacement or Rear Wheel Speed Sensor Replacement . Did you find and correct the condition? | -- | Go to Step 12 | Go to Step 5
5 |

1. Disconnect the wheel speed sensor harness connector.
2. Use a DMM in order to measure the resistance across the wheel speed sensor.

Does the resistance measure within the specified range?

1500-2500 ohms

Go to Step 6

Go to Step 8

6 |

1. Spin the wheel by hand as fast as possible.
2. Measure the AC voltage across the wheel speed sensor.

Does the AC voltage measure greater than the specified value?

800 mV

Go to Step 7

Go to Step 8

7 | 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 in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 12 | Go to Step 9
8 | Replace the wheel speed sensor. Refer to Front Wheel Speed Sensor Replacement or Rear Wheel Speed Sensor Replacement . Did you complete the replacement? | -- | Go to Step 12 | --
9 | Test the wheel speed sensor circuits for the following:

• | An open

• | A short to ground

• | A short to voltage

• | Shorted together

Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 12

Go to Step 10

10 | Inspect for poor connections at the harness connector of the EBCM. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 12 | Go to Step 11
11 | Important: Following EBCM replacement, use the scan tool to perform the Tire Size Calibration procedure and the Trim Level Calibration procedure. Replace the EBCM. Refer to Electronic Brake Control Module Replacement . Did you complete the replacement? | -- | Go to Step 12 | --
12 |

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 set?

--

Go to Step 3

System OK