C0221

DTC C0220-C0229

Diagnostic Instructions

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

DTC Descriptors
DTC C0220 00
- Left Front Antilock Brake System (ABS) Channel in Release Too Long

DTC C0221 00
- Right Front Antilock Brake System (ABS) Channel in Release Too Long

DTC C0222 00
- Rear Antilock Brake System (ABS) Channel in Release Too Long

DTC C0223 00
- Left Front Antilock Brake (ABS) Channel Motor Free Spins

DTC C0224 00
- Right Front Antilock Brake (ABS) Channel Motor Free Spins

DTC C0225 00
- Rear Antilock Brake System (ABS) Channel Motor Free Spins

DTC C0226 00
- Left Front Traction Control System (TCS) Channel Will Not Move

DTC C0227 00
- Right Front Traction Control System (TCS) Channel Will Not Move

DTC C0228 00
- Left Rear Antilock Brake System (ABS) Channel in Release Too Long

DTC C0229 00
- Right Rear Antilock Brake System (ABS) Channel in Release Too Long

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. This voltage is referred to as the system voltage. The EBCM microprocessor activates individual valve solenoids by grounding the valve solenoid control circuits. The power brake pump motor is internal to the brake pressure modulator valve (BPMV). The pump motor is not serviceable.

Conditions for Running the DTC

* The system and ignition voltage is greater than 8 volts.
* The system is in an ABS braking event.

Conditions for Setting the DTC

The EBCM commands a dump or isolation solenoid ON for greater than 28 seconds.

Action Taken When the DTC Sets

* The EBCM disables the ABS/Traction Control System (TCS).
* 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 you can use the scan tool clear DTCS function.
* The EBCM automatically clears the history DTC when a current DTC is not detected in 100 consecutive drive cycles.

Diagnostic Aids

The most likely cause of this DTC is a mechanical failure that causes a wheel to lock and remain locked. Always diagnose and repair any wheel speed sensor failures prior to diagnosing DTCs C0220, C0221, C0228, C0229. These DTCs in theory 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.

Reference Information
Schematic Reference

Antilock Brake System Schematics ([1][2]Antilock Brakes / Traction Control Systems)
Description and Operation

ABS Description and Operation (Description and Operation)
Connector End View Reference

Component Connector End Views (Connector Views)
Electrical Information Reference

* Circuit Testing (Component Tests and General Diagnostics)
* Connector Repairs (Component Tests and General Diagnostics)
* Testing for Intermittent Conditions and Poor Connections (Component Tests and General Diagnostics)
* Wiring Repairs (Component Tests and General Diagnostics)

Scan Tool Reference

Control Module References (Programming and Relearning) for scan tool information.

Circuit/System Verification

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

• If solenoid test failed, replace the EBCM.

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

Circuit/System Testing

1. Ignition OFF, disconnect the harness connector at the EBCM.
2. Test for less than 5 ohm of resistance between the ground circuit terminals 1, and 29 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 Pump Motor supply voltage circuit terminal 10 and ground.

• If the test lamp does not illuminate, test the voltage circuit for a short to ground or an open/high resistance. If the circuit tests normal and the B+ circuit Hydromax fuse is open test or replace the brake pressure modulator valve (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 (Verification Tests) after completing the diagnostic procedure.

* Brake Pressure Modulator Valve Replacement (Service and Repair)
* Control Module References (Programming and Relearning) for EBCM replacement, setup, and programming