Just bought a 2011 S60 T6 and I am getting a P0171 Bank 1 too lean and a P0172 Bank 1 too rich. How could it be too lean and too rich at the same time. Started it up and took the dipstick out. Just a little bit of whistling when I initisally take it out. Would this be an indicator of the PCV going bad?

 

How much vacuum is present at the dipstick tube? Too much means the valve is broken in the pcv box. Easy to change on the 6 cyl.

 

Enough to hear a short whistling when I take out the dipstick or the oil cap. Wanted to make sure if it was the PCV before I ordered it.

 

So, it wasn't the PCV. Changed it out. The only code I am getting now is the P0172.

 

did you check the intake to see if there's any residual oil etc on the intake tubing/MAF/throttle body? If the PCV failed, it seems plausible that some oil could have been sucked into the intake dirtying up the MAF or throttlebody.

 

I didn't. I had the garage change mine. I got a new MAF to put in it. Maybe that will take care of it.

 

Are you letting your service provider diagnose your trouble codes?

Or are you diagnosing this yourself and telling them to replace this or that?

If so, why are you not letting a hopefully trained professional that fixes cars for a living and hopefully has a tremendous amount of knowledge diagnose and fix your car?

Do you just like guessing, buying stuff that does not fix it and trying again?

 

I looked through forums and asked mechanics. The whistling is gone, so it did fix that issue.

 

So yes, you are self diagnosing, and purchasing parts that you hope will fix your codes. Congratulations, that has worked out good so far.