C0228

DTC C0220-C0229

Diagnostic Instructions

* Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions provides an overview of each diagnostic category.



DTC Descriptors
DTC C0220 00
- Left Front ABS Channel in Release Too Long

DTC C0221 00
- Right Front ABS Channel in Release Too Long

DTC C0228 00
- Left Rear ABS Channel in Release Too Long

DTC C0229 00
- Right Rear ABS Channel in Release Too Long




Diagnostic Fault Information






Circuit/System 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 of the brake pressure modulator valve (BPMV). This voltage is referred to as the system voltage. The EBCM microprocessor activates individual valve solenoids by grounding the valve solenoid control circuits.


Conditions for Running the DTC

* Ignition voltage is greater than 8 volts.
* The system is in a ABS braking 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 less than 5 km/h (3 mph) for 1.25 seconds.
* The total dump time for any dump valve has exceeded 9 seconds and the EBCM has not received a wheel speed signal from the corresponding wheel during this activity.



Action Taken When the DTC Sets

* The EBCM disables the ABS system.
* The ABS indicator illuminates.
* DRP function is degraded.


The actions above are maintained during subsequent ignition cycles until the EBCM completes a power up self-test. This test concludes when the vehicle achieves a speed greater than 13 km/h (8 mph) and the wheel speeds are verified by the EBCM.


Conditions for Clearing the DTC

* The condition for the DTC is no longer present.
* 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

* Always diagnose and repair any wheel speed sensor failures prior to diagnosing DTCs C0220, C0221, C0228 or C0229.
* DTCs C0220-C0229 may be set on surfaces that are nearly impossible to get traction on. If the DTC sets within these conditions, diagnosis of the ABS system may not be necessary.
* The most likely cause of this DTC is a mechanical failure.



Reference Information
Schematic Reference

Antilock Brake System Schematics ([1][2]Antilock Brakes / Traction Control Systems)
Connector End View Reference

Component Connector End Views
Description and Operation

ABS Description and Operation (w/JL4) (ABS Description and Operation (With RPO JL4))ABS Description and Operation (without JL4) (ABS Description and Operation (Without RPO JL4))
Electrical Information Reference

* Circuit Testing
* Connector Repairs
* Testing for Intermittent Conditions and Poor Connections
* Wiring Repairs

Scan Tool Reference

Control Module References for Scan Tool Information


Circuit/System Testing

1. Ignition OFF, disconnect the harness connector at the EBCM.
2. Test for less than 5 ohms of resistance between the ground circuit terminals 11 and 28 and ground.

• If greater than the specified range, test the ground circuit for an open/high resistance.

3. Ignition ON, verify that a test lamp illuminates between the B+ circuit terminals 1 and 18 and ground.

• If the test lamp does not illuminate, test the B+ circuits for a short to ground or an open/high resistance. If the circuits test normal and the B+ circuit fuses are open, test or replace the BPMV.

4. Ignition ON, use the scan tool to perform the solenoid test.

• If solenoid test failed, replace the EBCM.

5. If all circuits test normal, replace the BPMV.



Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

* Brake Pressure Modulator Valve Replacement (w/JL4) (Service and Repair)Brake Pressure Modulator Valve Replacement (w/o JL4) (Service and Repair)
* Control Module References for EBCM replacement, setup, and programming