GM Service Manual Online
For 1990-2009 cars only

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 32 km/h (20 mph) when the brake is applied or 19 km/h (12 mph) when the brake is released.

Conditions for Setting the DTC

The EBCM detects an erratic signal from both front wheel speed sensors for 105 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

Operating the vehicle on extremely rough terrain can set DTC C0223, C0227 or C0229 even if the system is functioning normally.

Thoroughly inspect connections or circuitry that may cause an intermittent malfunction. Refer to the following:

    •  Testing for Intermittent Conditions and Poor Connections
    •  Connector Repairs
    •  Testing for Electrical Intermittents
    •  Wiring Repairs

If the customer 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.
  2. Drive 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.

Step

Action

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 within the Conditions for Running the DTC as specified in the supporting text.

Does the DTC set?

Go to Step 3

Go to Diagnostic Aids

3

Inspect for poor connections at the 4-way 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 5

Go to Step 4

4

Important: Following EBCM replacement, use the scan tool to perform the Tire Size Calibration procedure.

Replace the EBCM. Refer to Electronic Brake Control Module Replacement .

Did you complete the replacement?

Go to Step 5

--

5

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

Does the DTC reset?

Go to Step 3

System OK