By-Pass Air Control (BAC) Valve (MILLENIA)
WARNING: This page is about a different car, the 2001 Mazda Protege, 2001 Mazda Millenia, 2001 Mazda MX-5 Miata, 2001 Mazda MPV, and 2001 Mazda 626. However, it is still accessible from the selected car via links, so may be relevant.
- On Millenia 2.3L, BAC valve is located on rear of front cylinder head. See Fig 1 . On Millenia 2.5L, BAC valve is located underneath throttle body. See Fig 2 .
- On all models, ensure engine is cold. Start engine and let it idle. Idle speed should gradually decrease as engine reaches normal operating temperature. If idle speed does not decrease, check coolant hose to BAC valve. Repair as necessary. If coolant hose is okay, replace BAC valve.