EML on

Harris.

Active Member
Apr 5, 2010
366
0
Essex Bruv
Hey guys my EML came on tonight. ive just plugged vagcom in and i have 4 codes.

16885 vehicle speed sensor implausable signal intermittant po501

16891 idle control system rpm higher than expected intermittant po507

16522 oxygen (lambda) sensor bank 1 sensor 2 signal too high intermittant p0138

17584 bank 1 o2 (lambda) correction behind catalyst control limit reached p1176

Now the first 2 codes have been there for a few weeks but never brought the eml on,i have cleared them down before but not bothered with them yet

the other 2 have only appeared tonight and are what brought the eml on i think.

ive had a look on ross-wiki and the second and fourth codes point to a vac/air leak, or a dodgy lambda probe. I replaced the probe 6 months ago with a genuine part.

the third code isnt listed on ross-wiki

and the first code i think is a dodgy speed sensor.

Now im thinking that its got a vac pipe probably split under the manifold as i cant see a 6 month old probe being faulty (well i hope not), so i shall smoke test it at work tomorrow. I also rebuilt my dump valve and replaced my N75 and cleaned and reset my throttle body on saturday.

my question is has anybody had the same faults and found the cure?
any help/ advice will be appreciated.
 

Pyro

Guest
You may need to replace the other lamber sencor as one can throw them both out ;)
 

8bit

Active Member
Feb 11, 2010
3,401
3
Aberdeen
You may need to replace the other lamber sencor as one can throw them both out ;)

WTF is a "lamber sencor"? Are you using a UK English keyboard? :D

I've had lambda sensor codes a couple of times, tend to just clear then then keep an eye out and they never come back so you might be lucky. I had one come up last April then another in Dec, although I had boost issues that time (sticking DV) so that may have thrown the fuelling out.

Start by doing that then scan it again every couple of days, see what comes back. As for the first two, I've never seen them but if it were me then I'd start with whatever the ross-tech wiki site suggests. Might be worth searching for the code numbers individually in here too, that's what I usually do, particularly if the code doesn't show on the ross-tech site.
 

8bit

Active Member
Feb 11, 2010
3,401
3
Aberdeen
Harris, did you ever get to the bottom of this? My EML came on driving back from work tonight, I've got the 16522 and 17584 ones relating to the lambda sensors...
 

Harris.

Active Member
Apr 5, 2010
366
0
Essex Bruv
Hi mate.

Yes it turned out to be the lambda probe after the cat. I had only replaced it 8 months earlier. The voltage for the probe was reading way too high. When I looked Into it the cause of it would either be a faulty probe or signal wire pin 4 back to the ecu. When logging the data the voltage was intermittently within spec so I figured if the wiring was short id have it all the time. Changed the probe and it's been fine. I checked this using the guided fault finding method for a TT ( as I work for Audi) but I can't remember the exact voltages it should be.

I've also seen on a few TT's and A3's the the connection for probe 2 under the floor can get water in it. Worth checking and putting some electrical contact grease in.

Hope you understand that.
 

8bit

Active Member
Feb 11, 2010
3,401
3
Aberdeen
Hmm ok cheers, might just go ahead and replace the sensor then, thanks :) I get lambda codes popping up every few months or so, guess maybe it really is dodgy.

Thanks for replying, cheers!
 

stubee

Active Member
Jul 13, 2010
190
0
Iwade, Kent
you all sorted now mate? is this the problem you was talkin about the other night? iv still got my running problem after changing the coolant sensor but still haven't dont the t/body as iv gotta get a new gasket. it only really does it if i do a short journey???
 
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