Circuit Description
The system relay is energized when the ignition is ON. The system relay supplies voltage to the valve relay. The electronic brake control module (EBCM) activates the valve relay to supply voltage to the valve solenoids. This voltage is referred to as the system voltage. The EBCM microprocessor activates individual valve solenoids by grounding the valve solenoid control circuits.
DTC Descriptors
This diagnostic procedure supports the following DTCs:
| • | DTC C0220 Left Front Antilock Brake System (ABS) Channel in Release Too Long |
| • | DTC C0221 Right Front Antilock Brake System (ABS) Channel in Release Too Long |
| • | DTC C0228 Left Rear Antilock Brake System (ABS) Channel in Release Too Long |
| • | DTC C0229 Right 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
This code is set when the following criteria are met.
| • | The EBCM is commanding a valve solenoid to release brake pressure. |
| • | The wheel that is commanded to release brake pressure has a speed below 5 km/h (3 mph) for 1.25 seconds. |
Action Taken When the DTC Sets
If equipped, the following actions occur.
| • | The EBCM disables ABS/TCS. |
| • | ACC Braking is degraded. |
| • | VSES is disabled. |
| • | The ABS indicator turns ON. |
| • | The traction off indicator turns ON. |
Conditions for Clearing the DTC
| • | The condition for the DTC is no longer present and the DTC is cleared with a scan tool. |
| • | The electronic brake control module (EBCM) automatically clears the history DTC when a current DTC is not detected in 100 consecutive drive cycles. |
Diagnostic Aids
The solenoid valve circuit is internal to the EBCM. The solenoid valve circuit is not diagnosable external to the EBCM. The DTC sets when there is a malfunction in the solenoid circuit internal to the EBCM.
Possible causes for this concern:
| • | Intermittent wheel speed sensor |
| • | Wheel speed sensor is equal to 0 km/h (0 mph) |
| • | Contaminated hydraulic unit |
Test Description
The number below refers to the step number on the diagnostic table.
Step | Action | Yes | No |
|---|---|---|---|
1 | Did you perform the Diagnostic System Check - Vehicle? | Go to Step 2 | |
Does the DTC reset as a current DTC? | Go to Step 3 | Go to Testing for Intermittent Conditions and Poor Connections | |
3 | Replace the electronic brake control module (EBCM). Refer to Control Module References for replacement, setup and programming. Did you complete the replacement? | Go to Step 4 | -- |
4 |
Does the DTC reset? | Go to Step 3 | System OK |
