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.
Pre-charge Bleed
The Pre-charge bleed procedure is to be performed when air may have been introduced into the precharge pump inlet hose, the precharge pump or the combination valve. Perform the procedure as follows.
- Ensure that the master cylinder reservoir is filled to at least the minimum-fill level with Delco Supreme 11, GM P/N 12377967 (Canadian P/N 992667), or equivalent DOT 3 brake fluid from a clean, sealed container.
- Ensure the master cylinder reservoir cap is ON securely.
- Install a scan tool.
- Turn ON the ignition.
- Select the VSES Special Functions menu on the scan tool.
- Select Pre-charge Bleed.
- Press the On key. The precharge pump runs for approximately 3 seconds, circulating fluid from the master cylinder fluid reservoir, through the precharge pump and combination valve, then back to the master cylinder.
- Evaluate the feel of the brake pedal. If the pedal feels spongy, perform a base brake system bleed. Refer to Hydraulic Brake System Bleeding (Manual) or Hydraulic Brake System Bleeding (Pressure) .
- Ensure that the master cylinder reservoir is filled to at least the minimum-fill level with Delco Supreme 11, GM P/N 12377967 (Canadian P/N 992667), or equivalent DOT 3 brake fluid from a clean, sealed container.
Use the Manual With the Right Hardware
Pair factory procedures with proven DIY tools so the instructions are easier to execute.
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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.
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