annnnnd... my CEL is on - code query

A6 All/ S6 All
#1

sooooo, after a whopping 1.5wks and a few tanks of fuel in my new to me '07 S6 - it threw a CEL. Fak! Figured was only a matter of time honestly, seems to be my luck!

odd part is, I sheepishly admit I’ve no clue ‘when’ it came on - my steering wheel rim completely blocks that upper quadrant of my cluster… d’oh

pulled the code, and got this: p1085-004 bank 4 mixture regulation lean limit exceeded

did a search here, didn’t find it

Googling reveals a slew of ugly issues that could be related to this - but ALL of those posts on forums were accompanied by a glut of “other” codes in conjunction… mine’s just this one

cleared it, came back on about 70-75mi later… this time I saw it, came on during a 15-20mi period of light throttle 50mph cruising in 6th gear

can anyone please share any insight they might have to point me in the right direction here?

thanks much in advance!

#2

You’ve come to the right place here for help.

Have you had your intake off recently? In say, the past two weeks?

Did you have any exhaust work done in the same time-frame?

If you have Vag-com check the LTFT data for bank 3 and 4. Then go into ECU 1 and check the LTFT data for bank 1 and 2

Check your intake manifold bolts to see if they are tight on the driver side. That would be a good place to start after checking the Vag-com data.

#3

Thanks for the reply, Count.

Yes I just had 3" pipes and an x-pipe run in place of the 2nd resonators and OE pipes last week, as well as I installed K&N’s.

The manifold was new @ 35k, now 94k. Valve cover gaskets were just done prior to my picking it up. Otherwise, no manifold work.

All injectors / coils were done @ 35k as well.

I’ll get VAG-COM hooked up per your suggestion and report back.

REALLLLLLLLY hoping it’s something stoopid / simple… oy.

#4

It wouldn’t hurt to take it back to your exhaust shop, and have them double check the nuts and bolts. Make sure everything is torqued. Plus one on the vagcom data first!

#5

Getting the exhaust checked out might not be a bad idea. Also getting the valve covers checked might not be a bad idea either the valve cover can cause a vac leak and that could effect fuel trims as well

#6

Subscribed; would like to know how it turns out.

MAF sensor may need cleaning or other related sesnor – shot in the dark guess.

Best of luck!

#7

soooo

Drove a day or so with the CEL back on… then <poof!>… it vanished. Schwing!

annnnnd then… it returned 1/2 day later. Farq!

Had my bud VAG it again, providing the instructions suggested above about LTFT’s etc. He was unable to locate banks 3/4, only banks 1/2 - any suggestions for VAGnoobz? :sunglasses:

So, the code was the same as the other time… but this time was accompanied with a 2nd code:

Bank 1; system too lean at idle - P2187-004 - Intermittent

He cleared them both and I’ve put on 200mi with the light still off <ducks! SHHHHH!>

any further thoughts on “all this” from the respected braintrust here?

I have noticed one one or three occasions now during coldish start that the idle is smooth then has a brief / sudden stutter, then returns to smooth - no CEL occurred tho during those stumbles. Related or normal? My bud says his RS6 does the same sometimes.

anywho