Circuit Description
During an ABS event, the electronic brake control module (EBCM) calculates the total time that a dump valve is energized while attempting to unlock a locked wheel.
DTC Descriptor
This diagnostic procedure supports the following DTC:
DTC C0228 Left Front 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 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/dynamic rear proportioning (DRP). |
| • | The ABS indicator turns ON. |
| • | The brake warning indicator turns ON. |
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 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 |
