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egt sensor location on '03 S3

Discussion in 'A3/S3 Forum (8L Chassis)' started by smest, Dec 21, 2010.

  1. smest
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    smest New Member

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    hi,can anyone tell me if this is the egt sensor on my car ?(circled in red) or is it the lambda?reason i ask is i saw another thread on this forum where the egt sensor has a black box at the end of the cable,the one on mine doesnt so im thinking it could be the lambda?also has anyone got any recommendations on where to buy a new egt sensor?cheapest i can get one is £145+vat from audi

    [​IMG]
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  2. MUSH
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    MUSH MUSH Developments Ltd.

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    Thats the wideband lambda probe.

    The EGT sensor is fitted into the housing directly on the the k04 turbo. A swine to get to!!!
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  3. smest
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    smest New Member

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    oh great,can you get to it from the top of the engine or will i have to get underneath and get dirty?
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  4. S3 Paul
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    S3 Paul Active Member Staff Member Regional Rep

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    It is possible from up top,
    A bit of a bugger but if you go round the gear box side of the engine... follow a thin braided wire around the side of the block to the turbo... i think its something like a 13mm or 15 mm spanner size. but i cant remember.
    Sorry
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  5. smest
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    smest New Member

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    does anyone know whereabouts the connector is situated for this?i have found the sensor on the turbo but i can only see where about 6 inches of the cable go to,seems to head towards the engine??does the turbo inlet hose have to come off to get this barsteward changed?
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  6. <tuffty/>
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    <tuffty/> Badger 5 Edition Staff Member Moderator

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    EGT probe is in the back of the turbo and requires a 17mm spanner... this can be got to from the top of the engine... the black box of tricks the EGT probe connects too is bolted under the inlet manifold... this can be got to by removing the trim panel in from of the inlet mani revealing the plug... you need to remove the metal plate to remove the black box.. 2 x 5mm allen bolts for the plate, 2 x 5mm allen bolts for the black box... the probes braided cable goes around the gearbox side of the engine and is a bit of a pig to undo..

    The part (if your are replacing it) is around £180

    <tuffty/>
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  7. smest
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    smest New Member

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    ah right so thats the same bit of trim you take off to get to the thermostat then?i had that off yesterday aswell
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  8. <tuffty/>
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    <tuffty/> Badger 5 Edition Staff Member Moderator

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    yarp :)

    <tuffty/>
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  9. superkarl
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    superkarl MAN OF STEEL

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    £180! jesus!
    any things to worry about running a car with egt sensor fault?
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  10. <tuffty/>
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    <tuffty/> Badger 5 Edition Staff Member Moderator

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    Yes... runs as rich as f00k when faulty or disconnected.... **** fuel consumption and low power...

    I buggered mine but found one for £50 on ebay.de... I couldn't even get it discounted through TPS... cost price is not much less...

    <tuffty/>
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  11. superkarl
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    superkarl MAN OF STEEL

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    thanks for that. had no idea it would cause such things, i just thought the mpg was like that haha.
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  12. Jade S3
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    Jade S3 270bhp 13.6 1/4 mile

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    With my faulty egt average consumption was 12l/100km(quarter tank 100km) and thats on the highway with 25% throttle. Before it was faulty i got between 2.9-7.5l/100km. Quarter tank 220km. My buddy repaired mine but it only lasted a week, he says the problem is vibration causes the solder to break away. Going tomorrow morning to audi to order a new sensor(£225 where i live) . Also noticed the car loses alot of power when the egt is faulty
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  13. badger5
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    badger5 RIP S3dave Site Sponsor

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    when ecu see's implausable type sensor issue from egt, or intermittent connection.... it fuel dumps, which murders power and economy :(

    watch block 112 kick in and 031 go mega rich when it gets into this fault condition
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  14. superkarl
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    superkarl MAN OF STEEL

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    i may remove and see if there is any damage to wiring that may be fixed first.
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  15. thorsy22
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    thorsy22 Member

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    When booting it the other day WOT highish revs 4k+ in 4th gear+ felt like I'd hit a limiter or wheel spinning (but not doing either) until I caught the engine light flashing.
    At first thought might be coilpacks on the way out but when I got home did a scan and got the following codes:

    17861 - Exhaust Gas Temp Sensor 1 (G235): Open or Short to Plus
    P1453 - 35-00 - -
    16684 - Random/Multiple Cylinder Misfire Detected
    P0300 - 35-00 - -
    16687 - Cylinder 3: Misfire Detected
    P0303 - 35-00 - -
    16686 - Cylinder 2: Misfire Detected
    P0302 - 35-00 - -
    Readiness: 0000 0000

    Cleared them all and rescanned again this evening and although I havent done any more WOT runs have got the EGT fault back.
    Does the ECU missfire to protect the turbo and CAT as it doesnt have reliable EGT sensor information or could the coilpacks be going aswell?

    Anyone got a pic of the plug for the EGT sensor if its under the intake manifold as was under there the other day changing the thermostat so hopefully the plugs just come loose!

    £180 for a new one :( anyone got a part number so I can hunt on ebay?

    According to this link The Audi TT Forum :: View topic - EGT sensor
    it could be a fuse, any ideas which ones to check?
    Last edited: Jan 11, 2011
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  16. s3dave
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    s3dave TFSI Hybrid

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    The egt is on the turbo housing not intake
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  17. thorsy22
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    thorsy22 Member

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    I understand the probe itself is on the turbo but what people are saying is that it plugs into the cars electronics somewhere under the intake manifold, just wondering if anone had a pic to show where this is.
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  18. s3dave
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    s3dave TFSI Hybrid

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    ahh i see, there are a few connectors above the thermostat housing, deep under the intake manni,not sure if one of them is the one...
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  19. mikes3
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    mikes3 Member

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    The connection block is literally bolted to the underneath of the inlet manifold ( lookin at my BAM engine ). The plug to the ECU is facing the front of the car, just an inch or so to the left of the dipstick, with the braided cable going off in the other direction.
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  20. s3gazz
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    s3gazz Active Member

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    my car is doing all of these mate but got maf sensor fault need new lambda sensor for down pipe and egt sensor 1 would one of them course that or all
    need changing car driveslike hell and drinks so much tar
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  21. thorsy22
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    thorsy22 Member

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  22. s3gazz
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    s3gazz Active Member

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    iv got the amk engine is these the one with the probe or not tar guys seen etg sensor on ebay for 30
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  23. thorsy22
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    thorsy22 Member

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    I have an AMK engine so yes.
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  24. karls s3
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    karls s3 Member

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    these egt sensor will they cause the car to idle rough and engine to shake about a bit.. i have this code come up on vag com did have lambda sensor 1 in the manifold but changed this and code has gone and not came back also cleaned the throttle body. and this code keep coming up and car is rough on idle when warm . any one else have same problem when they had this code
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  25. S3 Nattie
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    S3 Nattie Quattro ist für sissies

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    Just wondering do you have any links for the EGT sensor. I just been out logging and keep getting the code.

    Explains why im getting a stutter and really bad MPG.
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  26. <tuffty/>
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    <tuffty/> Badger 5 Edition Staff Member Moderator

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    No mate... bought it ages ago... think I just searched on Audi S3 or the part number which can be found on the black box under the inlet mani... it was the only one I found at the time but thats not to say its the only one on there...

    <tuffty/>
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  27. S3 Nattie
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    S3 Nattie Quattro ist für sissies

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    Ok thanks anyway Paul. Really hope its not the sensor as they are expensive, will have a look at the sensor and wire tomorrow. Will keep a nose out on ebay to see if one comes up cheap.
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  28. S3 Nattie
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    S3 Nattie Quattro ist für sissies

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    I just been out logging my lambda and my exhaust gas temps and there were as I expected with this EGT fault I got.

    On cruise my temps are around 600-700+ degrees but as soon as my foots down it goes straight to 1100 degree which I believe is the limit on vag com. I doubt my temps were that high but the sensor is giving duff readings. My fuelling when really rich too, 0.7 on a standard map and my boost dropped straight away and felt flat until the exhaust gas temps lowered.

    Im just wondering does anyone know where I can get a cheap EGT sensor from or if they have one spare they want rid of.
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  29. <tuffty/>
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    <tuffty/> Badger 5 Edition Staff Member Moderator

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    Wow! tbh mate other than a breakers/ebay you are unlikely to get one other than new from a dealer... there is now margin in them at the dealer (I have asked them and enquired with a mate who gets the best discount from TPS)... they are around the 170 quid mark all day long for whatever reason... prob due to the controller being part of the probe as the probe is nowt special just a type k thermocouple...

    I still have my old EGT probe kicking around and the only problem with it was when I tried to open the controller looking to see if there was an issue with the thermocouple I managed to knock a surface mount resister off the potted (flexible potting compound) pcb... it works intermittently but I was planning on getting the thing repaired as that is all thats wrong with it...

    If you want to pop up to Bill's place one Saturday and try it you are welcome...

    <tuffty/>
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  30. S3 Nattie
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    S3 Nattie Quattro ist für sissies

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    Cheers for that, if I have no luck finding one I may give your one a try. It such an expensive part for what it is and going from my data today its definitely not right. Im going to have a look at the wiring and measure the resistance too.

    I was surprised with the reading, on one point the ECU was requesting a lambda of 0.649 and my boost dropped by about 3-4 psi from looking at the gauge and just felt really flat. The temp readings were also quite mad, going from 600+ degrees straight to 1100 degrees. I would have thought around 900 degrees would be acceptable on a remapped car.

    Would you say something in the controller is broke or the actual probe you think. I might open mine up and see if there is anything obviously wrong.
    Last edited: Apr 16, 2011
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  31. <tuffty/>
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    <tuffty/> Badger 5 Edition Staff Member Moderator

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    EGT protection based on EGT probe readings kick in at 925 deg at which point it goes bonkers rich and the ECU switches off lambda correction..

    The controller is pretty robust tbh and isn't in a place that it is likely to get damaged... the probe however is more likely to be the culprit here especially as you are getting readings....

    The probes connection is potted inside the box which is one of the reasons I tried to open it...

    <tuffty/>
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  32. S3 Nattie
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    S3 Nattie Quattro ist für sissies

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    Ye I thought it was around that figure when the ECU protection kicks in, I assume 1100 degrees is vag coms limit then. This probably explains the reason why my mpg is so low and why my performance is only there once and then feels flat. I sometimes get a stutter/hesitation and my dv randomly dumps when pulling off after a quick blast. Would you say thats were my ECU has dumped a load of fuel in causing the slight stutter.

    I think its just given up the ghost now as its been running a bit weird for a while but thought it was the maf even though it was giving ok readings. It hasnt been touched or anything recently and like you say the controller is in a secure place, I think im going to open it up first and have a nose.
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  33. <tuffty/>
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    <tuffty/> Badger 5 Edition Staff Member Moderator

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    at 1100 deg the ECU should throw a fault code indicating that max EGT temp has been exceeded (or upper limit or something...) I had this code while running my OEM back box when I had my GT30 mapped first time around... all better now of course :)

    <tuffty/>
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  34. S3 Nattie
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    S3 Nattie Quattro ist für sissies

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    This is the code Im getting;

    17863 - Exhaust Gas Temp Sensor 1 (G235): Implausible Signal
    P1455 - 35-10 - - - Intermittent

    Il have a look at the wiring and that tomorrow and try and open it up and go from there. Its typical when I have some spare cash for mods something has to come up lol.
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  35. <tuffty/>
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    <tuffty/> Badger 5 Edition Staff Member Moderator

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    That seems like a wiring or controller fault to me... any other fault codes? generally if there are a few that pop up it could just be a bad earth or a connecter thats shared somewhere...

    <tuffty/>
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  36. karls s3
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    karls s3 Member

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  37. S3 Nattie
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    S3 Nattie Quattro ist für sissies

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    I did think the wiring could be at fault because of the implausible signal in the fault code. IRRC there is a earth under the battery. How did you open up your controller, I cant remember but there not screws on it to open it isi.



    Last edited: Apr 17, 2011
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  38. <tuffty/>
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    <tuffty/> Badger 5 Edition Staff Member Moderator

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    The controller is a sealed unit mate... opening mine is how I managed to bugger it up.... you 'should' be able to 'carefully' work around the lip of the 'lid' to remove it but it is glued and I slipped with a small screw driver knocking the resister off the PCB.. the components are potted in a flexible compound so care needs to be taken...

    I would be tempted to try another probe first to rule out the probe itself....

    <tuffty/>
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  39. S3 Nattie
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    S3 Nattie Quattro ist für sissies

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    I see what your saying. Im trying to source a cheap second hand one first and if that sorts the fault out il get a new one. £170+ is a bit expensive for a trial and error. If I decide to open it up il remember to be very careful :icon_thumright:
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  40. karls s3
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    karls s3 Member

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