Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
Circuit Description
Proper operation of the vehicle stability enhancement system (VSES) is highly dependent on the ability to apply brake pressure to a selected wheel, through the brake pressure modulator valve (BPMV), as commanded by the electronic brake control module (EBCM). The EBCM may not be able to detect certain mechanical failures that may cause the VSES to perform poorly. This diagnostic procedure is designed to help diagnose concerns of poor vehicle stability, that may occur without the presence of any DTCs, by verifying the following.
- The tires are the correct size, properly inflated and in acceptable condition.
- There are no mechanical problems in the steering system.
- There are no mechanical problems in the suspension system.
- There are no mechanical problems in the base brake system.
- All of the VSES related hydraulic controls within the BPMV are functioning correctly.
| Step | Action | Yes | No |
|---|---|---|---|
| 1 | Did you review the system Description and Operation and perform the necessary inspections? | Go to Step 2 | Go to Symptoms - Anti-Lock Brake System |
| 2 | Inspect all 4 tires for the following:
Did you find and correct a concern? |
Go to Step 11 | Go to Step 3 |
| 3 | Inspect the vehicle for following:
Did you find and correct a concern? |
Go to Step 11 | Go to Step 4 |
| 4 | Diagnose any suspension symptoms exhibited by the vehicle. Refer to Symptoms - Suspension General Diagnosis
. Did you find and correct a concern? |
Go to Step 11 | Go to Step 5 |
| 5 |
|
Go to Step 11 | Go to Step 6 |
| 6 | Diagnose any hydraulic brake symptoms exhibited by the vehicle. Refer to Symptoms - Hydraulic Brakes
. Did you find and correct a concern? |
Go to Step 11 | Go to Step 7 |
| 7 |
|
Go to Step 9 | Go to Step 8 |
| 8 | Perform brake pressure application testing. Refer to Brake Pressure Modulator Valve Hydraulic Testing . Did either of the TC isolation valve tests fail? |
Go to Step 9 | System OK |
| 9 | Replace the brake pressure modulator valve (BPMV). Refer to Brake Pressure Modulator Valve (BPMV) Replacement (w/JL4) or Brake Pressure Modulator Valve (BPMV) Replacement (w/o JL4) . Did you complete the replacement? |
Go to Step 10 | - |
| 10 | Use the scan tool to perform all of the available BPMV hydraulic tests. Refer to Brake Pressure Modulator Valve Hydraulic Testing . Do the hydraulic tests show the system to be functioning normally? |
Go to Step 11 | Go to Step 5 |
| 11 | Test drive the vehicle to verify that the stability concern has been corrected. Has the concern been corrected? |
System OK | Go to Step 2 |
NO RELATED
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.