The ABS relay supplies battery voltage to 6 valve solenoids. The electronic brake control module (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.
• | 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/VSES and DRP. |
• | The ABS indicator turns ON. |
• | The traction off indicator turns ON. |
• | The red brake warning indicator turns ON. |
• | The message center displays the SERVICE STABILITY 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 ABS Diagnostic System Check? | 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 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 |