2008 XC90 3.2L with codes P0171 and P0174 - Help

[Turbo_Boss]

Hey guys,

I have a 2008 XC90 3.2 AWD with 75,000 KMS that I got recently.

Checking with OBD FUSION, I got the codes:

P0171 and P0174 System Too Lean

P0507 Idle Air Control RPM Higher than expected.

The car feels and drives normal but I want to fix these before it gets worse.

Searching on the web for these codes P0171 and P0174 its look like maybe the problem is the PCV but I don’t find any info, pics or DIY fix for this issue on a 3.2L engine

Have any of you with 3.2L engine has experienced these same codes?

I going to check if I have a vacuum hose leak but can you advise were I need specially to look

Thank you for your time and help

Isaac

[MrWinkey]

Clean the throttle housing

[Fran9690]

I've seen the oil trap on top of the cam cover fail and cause lean codes. When it gets bad enough, you sometimes get like a slight squealing noise from the engine and when you pull the dipstick when running, the noise goes away and you can hear air rushing in. See if your car is doing the same.

[Turbo_Boss]

I've seen the oil trap on top of the cam cover fail and cause lean codes. When it gets bad enough, you sometimes get like a slight squealing noise from the engine and when you pull the dipstick when running, the noise goes away and you can hear air rushing in. See if your car is

Hey Frann9690,

You was right!

Searching on the web for these codes P0171 and P0174 its look like the problem is the PCV PCV OIL TRAP – VALVE COVER that have a bad the membrane/diaphragm.

Since the membrane/diaphragm is damage, it allow air to enter in the system that the MAF is not metering and that why it throw System Too Lean codes.

So a few days ago I was checking the black housing on top of cylinder head and the first thing I notice is that is all covered in oil.

Also notice a hissing noise that is coming from the engine oil cap. I removed the oil cap and put my hand over the hole and there is a "noticeable" suction.

I am thinking in ordering:
PCV OIL TRAP – VALVE COVER Part No. 31319642
VALVE COVER GASKET Part No. 30731243

Can you guys, let me know what’s the correct torque setting for the torx screws for the PCV OIL TRAP VALVE COVER?

UPDATE

So today I have more time to check the valve cover Oil Trap and in the name of the science, research and investigation :-)  I decide to remove the plastic cap on top of the diaphragm housing.  

I know other brands like VW and BMW sell the membrane/diaphragm alone so I was expecting to see if I can replace it and save some $$$
I went to a place where they sell OEM and aftermarket parts for BMW.  They were very similar but none of them fit or was the same.  

On the Volvo membrane/diaphragm there is a part No. CF W 3A  MB66-24

Doing a search on the net I don’t find anything under that part No. or something similar.

Anybody knows where can I get this part? If not, I will have to buy the complete valve cover oil trap :-(

Also, whats the correct torque setting for the torx screws for the PCV OIL TRAP VALVE COVER?

THX,

Isaac

 

 

[Fran9690]

As far as I know, you can't only replace the whole oil trap, can't get individual parts like the membrane to fix. A new oil trap from the dealer also comes with the gasket, so no need to order one of those as well. As far as the torque setting for the bolts, I'm not sure about that. Not a big bolt, so it can't be that much. I don't torque them down, I just snug them down with a 1/4" ratchet and I've never had one come back to this date **knock on wood**

[Turbo_Boss]

Hey Guys.

So yesterday, I change the PCV OIL TRAP – VALVE COVER Part No. 31319642 on my 3.2L and cleared/reset the P0171 and P0174 System Too Lean codes and now the engine is smooth and not misfires.

So today I was driving and my check engine light come on and these are the codes I get:
P0172 and P0175 System too Rich.

Any advice what to check? Or what other test to make with the OBD Scanner?

THX,

Isaac

Here is the screen shot of the OBD Codes and also the Term Fuel % on idle on Bank 1 & 2

 

[Fran9690]

You didn't pinch the gasket did you? If you didn't after you replaced the oil trap, I would unplug the ECM for a couple minutes to reset the adaptives. I've seen the codes return after replacement because the ECM still has the old values stored in the memory of how it was running before and it takes too long to adapt from a really lean condition to a normal running condition. Pulling the connectors to the ECM will basically reset everything and give it a fresh start. It will also clear the codes. I would do that and drive it and see if anything returns and report back.

[Turbo_Boss]

You didn't pinch the gasket did you? If you didn't after you replaced the oil trap, I would unplug the ECM for a couple minutes to reset the adaptives. I've seen the codes return after replacement because the ECM still has the old values stored in the memory of how it was running before and it takes too long to adapt from a really lean condition to a normal running condition. Pulling the connectors to the ECM will basically reset everything and give it a fresh start. It will also clear the codes. I would do that and drive it and see if anything returns and report back.

Hello Fran9690

I am pretty sure I didn’t pitch the gasket

Installing that oil trap was idiot proof I remove the old one, clean the superficies with very fine sandpaper in order to remove old gasket marks and then put the new one.  The new oil trap comes already with a gasket that’s look like silicone.

Engine right now feels smooth

I will look for the ECM fuse and remove it for 5 minutes and let see what’s going on.

I will keep you updated

THX for your time and help

Isaac