Hi,

I'm new the forum, I believe I'm posting this is in the correct area?

Anyway..

I have a VW polo 1.2 12v, 2002 9n (I've been told its a 9n).

Does this version have MAF/MAF sensor? I have a Haynes manual and there is no reference to a MAF? Perhaps it has another name?

After doing some research online the general position (I think) is after the air filter and before the throttle body. Now the Air filter is built into the cover on top of the car and that interfaces directly with the throttle body. Is it built into the cover or located elsewhere or perhaps the car doesn't have one?

My end goal is to clean it or even replace it, my car has been throwing a p0172 system too rich code (intermittent). When I bought the car I was told that the o2 sensor had been changed (garage could have lied), these are quite costly, I've also read the MAF could be causing the issue, therefore I want to try and clean it first etc...?

Thanks in advance for any help :)

Phil

First Welcome to the forum.

Your engine uses a MAP sensor that also contains the inlet temp sensor, it's fitted on the drivers side end of the inlet manifold (two torx screws) give it a spray with some carb cleaner as they do get gummed up with oil deposits

#11 on this diagram

Hello,

Thanks for the reply!

Great, thanks for the diagram

Hopefully after inspection I can gauge whether the MAF could be causing my P0172 engine code.

Is there something I should be looking out for as to whether the MAF isn't working correctly or broken?

Thanks again for your help!

Phil

Depending on what diagnostics you are using? you can select the MAP sensor and actually check the output, but as you'll see from this fault finding guide it's not on the list of possible causes for that fault code

I'm not using any diagnostic.

I forgot to mention I'm absolutely new to fixing cars. I'm at the stage of, take one part out, put a new part in (with difficulty!).

I was just going to see whether it is dirty or not. Clean it and if the code doesn't disappear then possibly take a chance and buy a new MAP. (Currently MAP is cheaper than 02 sensor on Eurocarparts)

I believe the O2 sensors have all been changed (again, garage could have lied). From my research it does seem like the MAP can cause this code. The MAP measures the air pressure and adjusts the fuel/air mixture accordingly. If this is faulty then it could be telling the engine to burn more fuel than needed, which would cause the 02 sensor to pick up too much c02 in the system, possibly causing the code? but also from my research there could be another several parts causing the issue.

Thanks again for your reply,

Phil

From experience on my car when the MAP sensor was gummed up with oil, it put on the EPC light, but it did'nt thow up the fault code you have.

It might also be an idea to inspect all the rubber pipes attached to the inlet manifold and throttle body for any splits or cracks as this would introduce unmetered air into the system so causing mixture problems

Ok, will give the MAP a clean anyway and look at the pipes.

Thanks again for your reply,

I'll let you know how I get on,

Thanks,

Phil

Just thought I'd give an update.

Thanks for all the information above, I managed to remove the MAP sensor, give it a clean and re-install it.

I cleared the codes on my car and so far the p0172 code hasn't return. Normally it takes a few days to re-appear so we'll see what its like in a week

I've attached a picture to show how dirty the sensor was.

Thanks again for everyone's help!

Phil