Hi y'all. Just bought this 2006 xc90 2.5t. Love it and bought it knowing it had a check engine light on. Codes are p0101 mass air flow circuit range performance problem, p0170 powertrain fuel trim (bank 1), and p2177 powertrain system too lean off idle bank 1

When I bought the car the guy said he changed the mass air flow sensor but did not fix problem so he took it back and got another one. Still no fix. He left it at that because he's moving to Florida and doesn't need the car.

The car runs excellent. No miss no hesitation. But still the code. Mpg seems to be less than what I've seen people getting but I drive all city. So that and the cel probably has something to do with it.

I need to fix the cel so I can smog it so I can register it.

I've looked for loose vacuum hoses only found one but that didn't fix it. Hooked up a fog machine to the intake after MAF but couldn't find any leaks. Sprayed starting fluid all over all the vacuum hoses I could find and no rise in rpm.

I'm lost now so if someone could help me please. Tell me what I should try next. Thank you in advance.

 

Check the pcv system. I'd safely say that 95% of the time people misdiagnose a MAF code by replacing a MAF sensor. What people fail to realize is that just because the code is for a certain component, it doesn't mean it's bad. I've probably cleaned 10 pcv systems to replacing 1 MAF replacement.

 

Thanks Damien. I'll try that tomorrow.

 

So I found the pcv line that from the top of the valve cover to the throttle body I think. Hose seems very hard. I'll need to find and pick up a new one. I took the oil cap off and put a plastic bag over it and the bag didn't get sucked in. If anything it looked to be under pressure. So how do I clean out my pcv system.

 

Remove the intake and either clean out or replace the pcv box ( I always recommend replacement). Also the pcv nipple ( part that's held onto the intake by the banjo bolt) needs to be replace. Clean the block ports and replace the pcv hose that you said was hard. You should probably clean your throttle body because I can guarantee you that there's a lot of build up in there.

 

So I took the intake off. Replaced the box and the line that was hard. I was able to clean out the banjo bult and hoses. The little plastic line that goes to the banjo bult cracked and I replaced it. Car still runs great. Cleared all the codes. Drove it around. Checked the codes again and the p0101 code is pending. The pcv system was definitely clogged. Before I replaced it I was getting smoke coming out of the oil fill. Now that it's clean and replaced its sucking a bag down. So its definitely under vacuum again and it needed replacing. But it doesn't seem to have fixed the problem. I don't think it's the case but could the problem be that I have a Bosch MAF and not a Volvo MAF. What else could it be if its not the pcv or the MAF.

 

Did you clean your throttle body?

 

Yes but it looked brand new so there wasn't any buildup on the blade at all on either side.

 

Hey this is Perrin. Don't know why my posts aren't posting. I did clean the throttle body but it looked brand new. Both sides of the blade were very clean. I don't think it is but should I try to replace the MAF again with a true Volvo one instead of the Bosch one the guy put in.

 

So after everything I've been through my brother in-law has the same xc90. Not thinking it would work I borrowed his MAF sensor reset the coads and drove around for about 50 miles. Lite never came back on. So I bought a true Bosch MAF and it works fine now. I'm not getting the mpg I thought I'd get but its better than it was with the bad MAF.

 

Just started this morning. I get the yellow triangle with the exclamation point when I apply my brakes! Why? Please help!

 

Only when you apply the breaks and then it shuts off after you start going again? Not personally knowing much about volvo's and how there warning light work or why they come on id say you may need new breaks or your abs is malfunctioning. I would think though that if it was abs the abs light would come on. One of these fine volvo techs here could probably answer your question better than I can but didn't want you to think that your questions wouldn't get some type of reply.

 

Probably a brake light bulb. Check the message display.

And it helps to open your own thread rather than hijack two unrelated posts.

 

Didn't think about the light bulb. Definitely check that too.