For 1990-2009 cars

### Circuit Description

The electronic brake control module (EBCM) energizes the appropriate isolation and dump valve solenoids to control hydraulic pressure applied to a brake circuit during an Antilock Brake System (ABS) event.

### DTC Descriptors

This diagnostic procedure supports the following DTCs:

• | DTC C0220 Left Front ABS Channel in Release Too Long

• | DTC C0221 Right Front ABS Channel in Release Too Long

• | DTC C0222 Rear Antilock Brake System (ABS) Channel in Release Too Long

### Conditions for Running the DTC

• | The ignition is ON.

• | The vehicle is experiencing an ABS event.

### Conditions for Setting the DTC

An ABS event lasting 36 seconds or longer occurs on any brake circuit.

### Action Taken When the DTC Sets

• | The EBCM disables the ABS/TCS/dynamic rear proportion (DRP).

• | The ABS indicator turns ON.

• | The brake warning indicator turns ON.

• | The ABS fault message is displayed.

• | The traction fault message is displayed.

• | The brakes message is displayed.

### 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

Always diagnose and repair any wheel speed sensor failures prior to diagnosing DTC C0220, C0221 or C0222.

These DTCs may set, theoretically, when the ABS is activated on surfaces that are nearly impossible to get traction on. If the DTC sets within these conditions, diagnosis of the ABS system is not necessary.

### Test Description

The number below refers to the step number on the diagnostic table:

1. Performing solenoid tests determines if there is a mechanical malfunction inside the brake pressure modulator valve (BPMV).

Step | Action | Yes | No
--- | --- | --- | ---
1 | Did you perform the Diagnostic System Check - Vehicle? | Go to Step 2 | Go to Diagnostic System Check - Vehicle
2 |

1. Use a scan tool in order to clear the DTCs.
2. Use the scan tool in order to perform the necessary Solenoid Tests. Refer to Scan Tool Output Controls .

Do the Solenoid Tests show the system to be functioning normally?

Go to Diagnostic Aids

Go to Step 3

3 | Replace the brake pressure modulator valve (BPMV). Refer to Brake Pressure Modulator Valve Replacement . Did you complete the replacement? | Go to Step 4 | --
4 | Use the scan tool in order to perform the necessary Solenoid Tests. Do the Solenoid Tests show the system to be functioning normally? | System OK | Go to Step 3