Air Cleaner Assembly - Vacuum Leak Topic is solved

Jewl1215 · Post by **Jewl1215** » 15 Oct 2018, 09:29

If the air filter cover does not fit snug, covering the entire air filter, would that cause a vacuum leak?

https://www.myswedishparts.com/oem-part ... dhcw%3D%3D

The top of mine doesn't completely cover the actual air filter when snapping it back in to place.

I can hear a leak coming from somewhere, while driving, when pressing down on the gas to move ahead faster, like a whine, from somewhere around the dash. I know the air filter is not close to the dash, but want to ask about that, in case.

I have 4 codes:
P2178, P2180, P2188, & P2190

2004 XC90 2.9 T6, 203k miles

Thanks!

Post by **RickHaleParker** » 15 Oct 2018, 13:23

All four of the codes are Long-term fuel trim. Yes a air leak can cause all of them.

Any air leak after the MAF sensor can be the cause.

If the air leak is on the intake side, you can locate it with starting fluid. With the engine cold, start the engine. Spray starting fluid around the intake, hoses ect. If there is a leak, it will suck in starting fluid and you will hear the engine surge. If the engine does surge, back off the starting fluid, you just want to find the leak not blow your engine to kingdom come.

Jewl1215 · Post by **Jewl1215** » 15 Oct 2018, 15:07

Thank you so much. Trying this as soon as I get home today. Will keep you posted.

Post by **ggleavitt** » 17 Oct 2018, 16:49

If the MVS cross-reference https://www.matthewsvolvosite.com/volvo ... ewer-codes is correct (no reason to suggest it’s not), and you have a portable copy of VIDA available, all the codes map out to a fuel-air mixture problem as RHP alludes above. Highly likely not the airbox (bottom rear of my ‘05 has been bulged since 2010) in my opinion, agree that whatever is happening is happening after the MAF.

Some language in VIDA for covering pretty much all 4 codes that are referenced:
The control module receives information from the heated oxygen sensor (HO2S) about the fuel / air mixture when idling at both the lower and upper part-load range. If the fuel / air mixture deviates from λ=1, the short-term fuel trim will compensate for this by adjusting the injection time so that λ=1 is achieved. When the short-term fuel trim makes an adjustment, the integrator median must be adjusted by the long-term trim. Diagnostic trouble code (DTC) will be stored when the long-term trim must be adjusted almost to maximum in the idle range.

All 4 codes suggest the Low value, verbiage in VIDA for possible sources:
Intake air leakage, high fuel pressure, leaking injectors, defective mass air flow (MAF) sensor , contaminated engine oil, oil level too high, defective heated oxygen sensor (HO2S)

Since this is a twin turbo T6, like the 2.5T it’ll have an intercooler system before hitting the throttle body, this is a positive pressure space. May also be a source of a low value if it’s leaking from there as well, at least in my mind. The XC90 T6 has some plastic ducts and paths over the top of the engine, there are a few posts of parts breaking or cracks developing on the intake side from repetitive heat cycles (this is almost a 15 year old car?).

If it was a 5 cylinder and you were complaining about an air sound as a function of acceleration, I might suggest that you check the short hose on the turbo output at the back of the engine bay but since this is a T6, there’s a direct connect to the turbos with clamps and o-rings. Nevertheless, there are a number of areas that can leak, would not hurt to walk it all, from air filter to throttle body-

: B6294T Intercooler path.JPG (40.69 KiB) Viewed 5805 times

Agree fully with the above suggestion to walk the intake path, just thought to add some info for the rest.

Out of curiosity, PCV service ever been done on this car?

Jewl1215 · Post by **Jewl1215** » 18 Oct 2018, 18:20

I checked the box to the air filter last night and it was not connected properly from the bottom. The air intake was loose from the bottom of it. I secured it as best as I could. I only have an OBD2 reader and tried it again. Two of the codes disappeared. The two codes left are P2188 & P2190. (Sorry about the typo).

I plan to try to clean the MAF on Saturday.

The PCV has not ever been serviced and have been looking into that - getting prices since I’m
Not too confident in myself to do it myself. It failed the glove test and has a tiny smoke coming from the dipstick. The throttle control module was serviced in 2011 and I plan to have that serviced, as well.

I hope this puts an end to this for now. Don’t really want to hear about O2 sensors next.

It was a 1 owner and properly maintained at Volvo for the last 14+ years. Speak to that dealership often and they told me the PCV had not been serviced before, and would recommend looking into that.

This site is so helpful. Thanks to everyone who has information for me. You input is very valuable to me. I am very grateful.

Post by **RickHaleParker** » 18 Oct 2018, 18:49

P0190 - ECM-280B: Fuel pressure sensor.
P0188 - (ASE): Fuel Temperature (Sensor B) Circuit High ... I don't think Volvo ever used P0188.

For the PCV, do the glove test. Tie down the glove so that it does not get sucked into the engine if it passes.
Fail: If the glove stands up. Pass: If the glove sucks down.

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Jewl1215 · Post by **Jewl1215** » 18 Oct 2018, 19:10

It failed. Blew up.

Those are the codes my OBD2 reader pulled.

I think Volvo Service said her car doesn’t have a fuel pressure sensor. I have it written down somewhere, but I’m pretty sure he said that for her year and model.

Jewl1215 · Post by **Jewl1215** » 18 Oct 2018, 19:15

I also already replaced the Turbo Control Valve that’s suits along side the air filter box. Thats probably how the box got knocked out of place. I didn’t notice it until I started looking around more yesterday.

Jewl1215 · Post by **Jewl1215** » 18 Oct 2018, 21:13

Sorry, meant P2188 & P2190.

Post by **RickHaleParker** » 18 Oct 2018, 22:27

Figured there was something wrong with the information. I could not find a fuel pressure sensor or a fuel temperature sensor.

Replacing a oxygen sensor (HO2S) should be the last resort. Keep looking for leaks in both the intake and exhaust systems.
-------------------------------------------------------------------

P2188 = ECM-262A Long-term fuel trim. Upper limit
P2190 = ECM-272A Adaptive lambda control, bank 2 .Upper limit

Diagnostic trouble code (DTC) information (Applies to both ECM-262A & ECM-272A)

Condition
The control module receives information from the heated oxygen sensor (HO2S) about the fuel / air mixture when idling at both the lower and upper part-load range. If the fuel / air mixture deviates from λ=1, the short-term fuel trim will compensate for this by adjusting the injection time so that λ=1 is achieved. When the short-term fuel trim makes an adjustment, the integrator median must be adjusted by the long-term trim. Diagnostic trouble code (DTC) ECM-262A or ECM-272A will be stored when the long-term trim must be adjusted almost to maximum in the idle range.

Substitute value
none

Possible source Upper limit:

intake air leakage
exhaust system air leakage
defective heated oxygen sensor (HO2S)

Lower limit:

intake air leakage
high fuel pressure
leaking injectors
defective mass air flow (MAF) sensor
contaminated engine oil
oil level too high
defective heated oxygen sensor (HO2S)

Fault symptoms
none