1998 Mazda 626 ES, AutomaticFACTORY OEM SERVICE PROCEDURE

By-Pass Air Control (BAC) Valve: MPV

BAC valve is mounted to dynamic chamber, near throttle body. Remove BAC valve. Circulate cold water in BAC valve coolant input hose to cool valve. Circulate hot water in BAC valve coolant input hose and ensure air valve operates. Replace BAC valve as necessary.

Fig 1: Identifying BAC Valve (Millenia 2.3L)
G97C07234Courtesy of MAZDA MOTORS CORP.
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When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

  • β€’ You smell fuel, burning insulation, or see smoke.
  • β€’ Brakes feel soft, pull hard to one side, or make grinding noises.
  • β€’ The engine overheats, stalls repeatedly, or misfires under load.
  • β€’ You are missing required tools, torque specs, or safe lifting equipment.
  • β€’ You are not confident in the next step or safety outcome.

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