Hi everyone!
I'm the proud new owner of a 2010 S40 with the 2.0 B4204S3 engine. Idle's a bit up-and-down. I want to get to the mass air flow sensor and give it a clean.

1. Is the MAF really located in this location? (bottom of the right-most inlet manifold)
2. If so, what's the best way to take it out? Do I have to remove the whole manifold?

A picture I found of the manifold on a Focus with the same engine)

Is this where the MAF is? If so, how best to reach it?

 

See if this helps...

the MAF is a round tube with a connector going into it that's located just before the intake air tubing goes into the intake manifold. You can clean it with a MAF specific product like CRC MAF Cleaner (don't use ordinary carb cleaners as they may be too harsh). Also inspect the intake tubing for dirt or oil. If you see oil, it may be a sign that your PCV oil separator is failing and needs replacing.

Rough idles are more commonly caused by vacuum leaks so look around for any torn vacuum lines or cracks in the intake air tubing = you may need to spray around the intake tubes, injectors, mainfold gasket to see if any gets sucked in. I like to use something flamable like carb cleaner for this as when it sucks in it will bump the idle. If you have a hard time finding anything a smoke test may be in order as some of the tubing can be hard to see. Also scan for any stored fault codes.

 

Hiya! Sadly, that video is only helpful for people with the Volvo modular engine (other variations of the B4204). The S3 designation is for the Mazda/Ford engine, which has a plastic inlet manifold and the location of the MAF is different. It is at the bottom of the right-most pipe of the inlet (why? I have no idea).

EDIT: Perhaps I should specify, this is NOT a US-based vehicle. I'm in South America, so we got the Duratec 20 engine instead of the Volvo modular one.

 

either way you should be able to find the MAF and inspect the intake tubing. The S3 isn't listed on the Volvo modular engine wiki but usually the last digit is the engine's iteration which as you suspect could be only available in regional markets. Usually the iteration differences are external ie different engine management systems etc but the block is likely to be the same as the prior models.

 

The S3 is not listed on the Volvo modular engine wiki because it's not a Volvo engine. The S3 and S4 designations belong to the Mazda L/Ford Duratec 20 engine, as I mentioned before.

I know where the MAF sensor is (bottom-right of the intake manifold). I just want to know the easiest way to get there on my car.

Through the top? Do I remove the whole air filter housing? Or through the bottom? Is there enough space? Do I have to remove shielding?

Stuff like that.

 

But thank you very much for trying to help so far!

 

Did you found it? I'm still looking for the MAF, I dont want to take the housing off either. Cleaned the throttle and couldn't find it. Post photos if you have any

Edit: Just found out our model has a tMAP sensor instead, located under the intake mainfold, as you pointed out.

Edit 2: I did it, but had to remove the cooling fan .

Remember to clean it only with maf cleaner, I've seen people cleaning with break cleaner but could lead to false readings due to residues.

Saludos from Chile!

 

Honestly, I just gave up and took it to a trusted mechanic to take the manifold off and deal with it. I like the car too much to risk effin it up, and I live in an area where parts are not accessible or cheap.

I'll do my best to take pictures if he's not done by the time I go there Monday afternoon.