Circuit Description
The electronic brake control module (EBCM) internal relay supplies battery voltage to all 8 valve solenoids and to the pump motor. The EBCM microprocessor applies the grounds needed to activate each solenoid. The low side of each solenoid coil has a feedback circuit to the EBCM microprocessor. When a solenoid is commanded OFF, the feedback voltage is high. When a solenoid is commanded ON, the feedback voltage is low.
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 C0222 Rear Antilock Brake System (ABS) Channel in Release Too Long |
| • | DTC C0223 Left Front Antilock Brake System (ABS) Channel Motor Free Spins |
| • | DTC C0224 Right Front Antilock Brake System (ABS) Channel Motor Free Spins |
| • | DTC C0225 Rear Antilock Brake System (ABS) Channel Motor Free Spins |
| • | DTC C0226 Left Front Traction Control System (TCS) Channel Will Not Move |
| • | DTC C0227 Right Front Traction Control System (TCS) Channel Will Not Move |
| • | 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
The EBCM commands a dump or isolation solenoid ON for greater than 28 seconds.
Action Taken When the DTC Sets
If equipped, the following actions occur:
| • | The EBCM disables ABS/TCS. |
| • | The ABS indicator turns ON. |
| • | The traction off 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
The most likely cause of this DTC is a mechanical failure that causes a wheel to lock and remain locked. The DTC may also set, conceivably, 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.
Step | Action | Yes | No |
|---|---|---|---|
1 | Did you perform the Diagnostic System Check - Vehicle? | Go to Step 2 | |
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 |
