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.
Combination Air By-Pass Control Valve
The combination Air By-Pass/Air Control valve is used with some MAT systems. The valve combines functions of two normally closed valves in one unit. There are bleed type and non-bleed type valves; both look alike. Bleed type valves will have percentage of bleed rating molded on the side of the case. The by-pass portion of the valve releases air into the atmosphere, while the control valve portion re-directs the air.
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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.