error light on dash but no codes...

[lincoln_dj]

the 2004 audi a3 3.2 i've just bought has error light on dash, but apparently audi themselves can find no fault codes on diagnostic. has anyone come across this before? is it at all possible that all is well with the car and that whatever chip/wire/etc that tells the dash to display a error light is broke, rather than anything on the engine or ecu??

Cheers, Adam

[NHN]

Pic of icon please so we can ascertain what it is 1st.

[lincoln_dj]

yeah sorry nigel, it's the "emissions control" icon.

[NHN]

It could just be a thrown dtc code advising of an error in another module mate, but have you tried vagcom on the car as yet mate apart from audi diag?

[lincoln_dj]

not yet, a mate has one but it is lent out at the moment. and have had an offer of help from a chap on here about 40 miles away with the vcds.

is there things the vag com system can show up that audi diag wouldnt? you'd have thought if audi dont know then no one will!

[bearthebruce]

That is refered to as the MIL indicator. If it is on, there should be a DTC stored.

I don't know how to reply to the Audi tech not finding an error. That seems real strange to me.

Could it be a malfunctioning instrument cluster? Sure. We won't be able to help further without a full scan by a factory level diagnostic tool like VCDS or the Audi factory tool.

[NHN]

is there things the vag com system can show up that audi diag wouldnt? you'd have thought if audi dont know then no one will!

The thing is, the scan is sometimes only as good as the person doing the checks mate, so obviously cant comment on the diag by audi, but as Bruce says could be a cluster fault, but for sure if its lit up then there should be log to show this if cluster is working as it should, which is why I advise a vagcom scan to make sure the audi scan was done correctly.

[lincoln_dj]

was a camshaft speed sensor / engine speed sensor correlation fault. camshaft sensors were changed apparently. cleared it using vcds and seems to be ok so far

[NHN]

So you found these error logs when using vagcom then or what?

[lincoln_dj]

yep. so god knows why audi in notts couldnt clear the engine check light!

[NHN]

You should buy yourself vagcom mate, nudge nudge wink wink PM me if interested as I sell the genuine cables.

[bearthebruce]

- as I said, I can't for the life of me understand what went on with the Audi tech.

[NHN]

Bad day I'd say Bruce

[lincoln_dj]

yeah i will get round to buying one dont worry. the one my mate has looks like a copy cable, and uses serial port anyway which my laptop doesnt have.

[lincoln_dj]

light came on again today below is a paste of what the vcds software throws up.

VAG-COM Version: Release 409.1-S


Scan: 01,02,03,08,09,15,16,17,19,25,37,42,44,46,47,52,55 ,56,57,69,75,76,77,7D

Chassis Type: 8P - Audi A3/S3
Scan: 01,02,03,08,09,15,16,17,19,25,37,42,44,46,47,52,55 ,56,57,69,75,76,77,7D

-------------------------------------------------------------------------------
Address 01: Engine
Controller: 022 906 032 CA
Component: MOTRONIC ME7.1.1 5629
Coding: 0000172
Shop #: WSC 06435
1 Fault Found:
17755 - Camshaft Position Sensor 2 (G163) / Engine Speed Sensor (G28): Incor. Correl.
P1347 - 002 - Lower Limit Exceeded
Readiness: 0000 0000

-------------------------------------------------------------------------------
Skipping Address 15-Airbags

End --------------------------------------------------------------------------------------------------

any ideas what would make this appear??

[bearthebruce]

I believe that your engine uses variable valve timing. This error indicates that something is out of sync between the CAM and Crank timing. There is too much difference between them. Here is some more information from the Ross-Tech Wiki: 17755

[NHN]

I had that same error on my S3, but only after a cambelt change, so stands to reason its linked to this, as I swapped sensors & made no difference.

[lincoln_dj]

cheers for the info bruce.

nigel, how did you get rid of the error? assuming you did!

the sensors have apparently been changed so looks like the timing chain needs attention. guess cam cover needs to come off in order to make sure the TDC marks on the cam/crank rollers line up??

[NHN]

The car worked perfectly & came & went & came back, car got sold & no reports of issues from buyer, but I'd get the chain checked mate for sure.