P0101 and P0172

2001 Volvo S40. Check engine light popped on with codes P0101 and P0172. Any suggestions on what this means and what I should do to fix it?

FYI, any responses are very much appreciated, but let me warn you, they probably need to be written such that a trained monkey would understand them. I'm an attorney - not a mechanic...

Thanks!

Welcome!

Does this help? (read these two articles)
http://www.obd-codes.com/p0101
http://www.obd-codes.com/p0172

With the PO101 meaning not enough air flow across the mass air flow meter and P0172 meaning not enough air and too much fuel across the oxygen sensor it could be as simple as a clogged air filter or something in the air box causing air flow to be lowered or a bad or dirty mass air flow meter.

Thanks for responding!

I changed the air filter yesterday. It was very dirty. It had probably been a few years.

Regarding the mass air flow sensor - when I bought the air filter I bought some MAF cleaner. But, upon popping the hood I realized that I don't really know how to locate and/or how to get to it. I see where I think it is, but if that is it, there doesn't seem to be an easy way to get to it.

Pardon the terminology of the following. I'm sure I'm using all the wrong words. On the air "pipe" coming off of the "housing" where the air filter is stored, about 3 inches from the "housing", there is a electrical "attachment" which can be unplugged. I'm guessing this "attachment" is the electrical wiring for the MAF sensor. Does that sound right? Also, if this is it, should there be pretty easy access to the MAF sensor? Because I can't seem to get to whatever this "attachment" is attached to without detaching the air "pipe" from the "housing," which from looking at where the screws are, could be quite an ordeal. I'm afraid I might be missing something, because from everything I've read, the MAF sensor is usually pretty easy to get to.

If you made it this far, thanks for reading! Any help is appreciated!

If the air filter has been in there for FEW years then I bet it was the problem. And yes that is your mass air flow meter. I would cear the code and drive it before doing anything else.

I tried clearing the code but it popped back on after a few miles of driving. I should probably add that the car has been driving a little funny since the check engine light's been on. It doesn't idle consistently, and at start up it takes I'd say a full second to turn over. From what I've read though, there's a good chance that that's caused by the dirty MAF sensor. Do you agree?

So about actually getting to the MAF sensor - do you think I have it right that to get to it I have to disconnent the "pipe" from the "housing"?

My picture shows that the mass air flow sensor bolts directly to the top half of the air box with two size t25 torx screws on one end and the other end has the intake hose connected to it. There is a big O ring that my come out with the sensor that goes into the air box so make sure it goes back in. Also understand that cleaning sometimes don't fix you may have to replace it.

Did you ever get your problem fixed? The same thing is happening to me and i wanted to know what you did to yours to eventually fix it.