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

• | The ignition is ON.

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

### Conditions for Setting the DTC

Either of the following conditions may cause DTC C0238 to set.

• | The EBCM detects that one wheel speed is 20 percent greater than or less than the other wheel speeds.

• | All 4 wheel speed inputs are greater or less than each other by at least 8 percent.

### 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

Installing one or more tires of significantly different size on the vehicle may set DTC C0238. Operating the vehicle with one or more tires that have very low air pressure may also set this DTC.

Step | Action | Yes | No
--- | --- | --- | ---
1 | Did you perform the ABS Diagnostic System Check? | Go to Step 2 | Go to Diagnostic System Check - ABS
2 | Inspect the vehicle tires in order to ensure that all of the tires are the same size. Are all 4 tires of equal size? | Go to Step 3 | Go to Diagnostic Aids
3 | Inspect the wheel speed sensors and tone wheels in order to ensure they are the correct application and that they are clean and undamaged. Did you find and correct the condition? | Go to Step 4 | Go to Diagnostic Aids
4 |

1. Use the scan tool in order to clear the DTCs.
2. Operate the vehicle for 3 km (2 mi) within the Conditions for Running the DTC as specified in the supporting text.

Does the DTC reset?

Go to Step 2

System OK