The system relay is energized when the ignition is ON. The system relay supplies voltage to the valve solenoids and the pump motor. This voltage is referred to as the system voltage. The electronic brake control module (EBCM) microprocessor activates the valve solenoids by grounding the control circuit.
This diagnostic procedure supports the following DTCs:
• | DTC C0269 Excessive Dump Time |
• | DTC C0274 Excessive Isolation Time |
• | The ignition is ON. |
• | The vehicle is experiencing an ABS event. |
The EBCM commands a dump solenoid ON for 9 consecutive seconds.
The EBCM commands an isolation solenoid ON for 255 consecutive seconds.
If equipped, the following actions may occur:
• | The EBCM disables the ABS/TCS/DRP. |
• | The ABS indicator turns ON. |
• | The TRACTION OFF indicator turns ON. |
• | The red Brake warning indicator turns ON. |
• | The DIC displays the SERVICE BRAKE SYSTEM message. |
The conditions for setting the DTC are no longer present and you use the scan tool Clear DTCs function.
The most likely cause of DTC C0269 or DTC C0274 is a mechanical failure that causes a wheel to lock and remain locked. The DTCs 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.
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 Control Module References for replacement, setup, and programming. 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 |