I have a 2000 MPV. It periodically makes a humming sound that comes and goes at random, but only when outdoor temperatures are cool. The sound only occurs at low speeds and may cease when braking or accelerating, but not always. It sounds like it's coming from the engine compartment. The dealer told me to bring it in next time it makes the noise, but it is so random and of short duration that this is impossible. Any ideas?

 

Hello. We too have a 2000 MPV with the exact same intermittent humming sound. Kind of a low frequency noise, that sometimes goes away when we rev the engine but not always. If the radio is off you can really notice it. Anyone out there know what this is? Normal or something to check? Thanks. Blazers77

 

Very good probability is that the noise is coming from the Idle Air Control Valve. Might try disconnecting the electrical connector while noise is present and if the valve is at fault then noise will immediately stop. Updated IAC valve is available to correct problem. OE part number gy01-20-660a.
Little drawing below to show you where the valve is at. Very easy to replace.

[IMG]local://upfiles/1377/8E7D02216AAB4E90A22186DBC87590D0.gif[/IMG]

 

Thank you for this, our 2000 mpv has been humming for about 2 years now, and we could NEVER figure it out!. It is now throwing code 1518...idle speed control...looking forward to fixing it...love the car, it has 175k miles on it, and really only given us problems starting at about 150k miles...baby huey, your info is great!

 

Glad to hear that the information was usefull to you JOHNT50.
I don't think however that replacement of the IAC is going to solve the CEL. P1518 is stored for IMRC or Intake Manifold Runner Control stuck open. See link below to a thread on this.

https://www.mazdaforum.com/m_12806/tm.htm

https://www.mazdaforum.com/m_8634/tm.htm

 

I am having the same problem with my 2000 Mazda MPV. The humming was less frequent with the first/original engine. I recently had the engine replaced, because of a cracked block,and now the humming sound is driving me crazy.Especially since the temperatures have dropped here inGeorgia. The humming only occurs when it is cold outside. Thanks for the babyhuey! I'm going to work on repairing it today