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HELP! 2009 Mazda3, check engine light, PO101 error code for Mass Air Flow

My check engine light keeps coming on sporadically and giving me a PO101 error code…then I’ll reset it after making sure my MPG hasn’t dipped a significant amount (which is my “concrete” way of gauging if it’s performance is impaired) and it’ll come on 1-600 miles later. There’s no consistency in environment or conditions that are triggering this sensor, at least it’s not obvious to me. I finally looked under the hood at the filter and it’s a little dirty, but not nearly dark enough for it to be the problem. Any ideas on I’m getting this code and how to fix it?!

Clueless Kat

In order to fix it someone has to check out the functioning of your MAF sensor, its wiring, and even the MAP sensor if this vehicle is equipped with one. (Off the top of my head, I don’t know).

You might find this link helpful:

There are products that can be used to clean the MAF but that is not likely to help in this case.

Yup, I’m very familiar with that page. :confused:

What’s the function of the MAP sensor besides letting me know it’s not working properly?

Most MAF sensors are multiple sensors in one.

One part of the sensor detects air flow.
Another part of the sensor can detect the temperature of the air.

If one of those two parts of the MAF sensor breaks, it can set a code, like in your case.
Chances are, you need to have your car inspected by a mechanic who has data logging tools so that he can see if the air flow reading is faulty under certain rpm conditions, which is something you might only encounter on rare occasions on your normal driving of the car.


GREAT, now I somewhat understand it. Thanks for all the help!