[phuz]

Wife's car has thrown a CEL for about a week now. At first I thought dirty air filter because it has been a while since it was changed. Unfortunately not the problem.
I reset the CEL and while sitting there idling for 5 minutes, it comes right back.

I monitored the two O2 sensors in VIDA, and the rear sensor voltage would constantly cycle from low to high, as shown in the pictures below. Not sure if this is normal operation, and the rear O2 should have nothing to do with running rich, IIRC.

VIDA says:

Possible source
Clogged air filter.
Leak of crankcase ventilation.
Oil level too high.
Contaminated engine oil (gasoline mixed in oil).
Leaking injectors.
Leaking EVAP-valve
High fuel pressure.
Damaged mass air flow sensor.

Fault symptom
Malfunction indicator lamp (MIL) lit.
Poor performance.
Engine misfires.

However, performance is fine and there are no misfires.

 

[qaz996]

With the engine idling (after already being brought to operating temperature), lift the hood and remove the engine cover to gain access to the oil trap. Nearest the right side of it (as you are looking into the engine compartment), there will be a circular cover in the plastic. Toward the left side of that circle is a tiny hole. If you cover that hole with your finger and feel suction, try replacing the oil trap.

 

[phuz]

With the engine idling (after already being brought to operating temperature), lift the hood and remove the engine cover to gain access to the oil trap. Nearest the right side of it (as you are looking into the engine compartment), there will be a circular cover in the plastic. Toward the left side of that circle is a tiny hole. If you cover that hole with your finger and feel suction, try replacing the oil trap.

Well, there is a slight suction there. But what really got me is when I removed the oil filler cap, there was a LOT of suction and a loud woosh of air rushing in. I put the cap back, waited a few seconds, removed it again, and once again lots of suction. We've also been hearing this noise (squeaking/chirping) that I thought was the serp. belt, and have delayed doing it because it looks like a huge PITA on the XC60, but I noticed when I put the oil filler cap back on, it would make that noise again and it would go away as soon as I relieved the vacuum.

I'm also overdue on an oil change, so I will change that today and give it a good run.

Still thinking oil trap?

 

[qaz996]

Excellent observations!

Now I'm almost certain it's the oil trap. :thumbup:

 

[phuz]

Installed the new oil trap today. Vacuum is significantly reduced; however, CEL came right back.

I checked the MAF signal. It seems to be reading accurately. I gave it a few revs and the signal jumped as expected. The air filter is new. The oil is fresh. What is my next likely culprit?

Possible source
Clogged air filter. No
Leak of crankcase ventilation.
Oil level too high. No
Contaminated engine oil (gasoline mixed in oil). Doubtful since oil is fresh
Leaking injectors.
Leaking EVAP-valve
High fuel pressure. No
Damaged mass air flow sensor. No

 

[qaz996]

So you have VIDA?

Clear the code again and then go into Vehicle Communications tab and then ECM. Go to Advanced and find Reset Adaptations. Click on that.

Then drive the car and see what happens.

 

[phuz]

So you have VIDA?

Clear the code again and then go into Vehicle Communications tab and then ECM. Go to Advanced and find Reset Adaptations. Click on that.

Then drive the car and see what happens.

I thought about that, but didn't do it yet. So you think it could still be using the old adapted values?

 

[phuz]

Reset adaptations and CEL this AM. Wife drove it about 20-25 miles over several stops and it hasn't come back yet. We'll see.


Sent from my iPhone using Tapatalk

 

[phuz]

50+ miles so far and it hasn't returned. I guess that was it. It must have been trimmed out to the max. I'm curious if the adaptations would have fixed themselves over time and the CEL would have eventually shut itself off.

 

[beachnut]

Glad I found this thread, and thanks to phuz and qaz for the comments. I also had P0172 for a couple months on the S80 T6 and figured it was the oil trap. Just installed it today but couldn't get the pesky code to go away. Every time I'd reset it would come right back. Then I started thinking it was a maf, or fps, or evap valve, but I found this thread and reset the adaptations. Never would've thought about that. I haven't driven the car much yet, but so far so good.

 

[Bunnspeed]

At what mileage are you guys changing your oil trap? Is it an easy job? How do you know when it needs to get done?

 

[beachnut]

Our S80 has 86K miles. There's not really a specific code, just other conditions/codes that point to the pcv as a possible cause. The one symptom that seems common on the P3 (and P1's) is a whistling or squealing noise that is lessened or canceled by lifting the dipstick a little. I didn't find the job hard, but take your time on the rear 3 bolts holding the trap down and don't drop them or your T30. I've changed out pcv's multiple times on P80's and P2's so I'm used to working by feel. A 1/4" drive set with extensions and a swivel works well as the 3/8" drive was too bulky. A long T30 like these would be ideal. I have a few of those but not a T30. The biggest issue is that the pipe from the airbox to the turbo is in the way, plus it's really tight back there up against the firewall mat. I pulled the airbox end of the pipe off and also loosened up the cowl under the wipers. I did not loosen the air pipe on the turbo side. One of those three bolts has a hold-down under it that's attached to the air pipe by the turbo but mine had broken away from the pipe. Here's a good thread about the repair: http://forums.swedespeed.com/showthread.php?260201-Oil-Trap-Breather-Box-Cleaning-and-or-Replacement

 

[Bunnspeed]

Thank you for the info!

 

[VolvoDad72]

50+ miles so far and it hasn't returned. I guess that was it. It must have been trimmed out to the max. I'm curious if the adaptations would have fixed themselves over time and the CEL would have eventually shut itself off.

Thanks to you all for living your best Volvo lives and documenting the common failures and repairs for the world. Great to know how others sort the same issues...

2013 XC70 T6 with 122k miles. CEL with P0172 running rich, excessive vac at the oil filler and found the PCV diaphragm had split. Replaced PCV, reset light with cheapo code reader but CEL returned ASAP at ~600rpm same as phuz above.

I don't have VIDA to reset the "Adaptations". Will this simply sort itself after a set number of hours/miles? Or some other way to reset?

Would love to know if there is something else down the line causing this but as the diaphragm was obviously bad and the vac symptoms are resolved seems like all that is left is a computer issue.
Thanks so much.