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Exhaust Gas Temperature Sensor P2080 Merc W204 C250 Cdi

Discussion in 'Engine, Drivetrain, Fuel and Exhaust' started by Richard Stanton, Jan 9, 2019.

  1. Richard Stanton

    Richard Stanton Member

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    Hi, I have a C250 cdi on a 12 plate, W204 model. Can anyone tell me where I will find the 'Exhaust Gas Temperature Sensor', I know its on the exhaust manifold somewhere but I would appreciate anyone who has expirence fitting these to provide some direction or pictures if possible of where exactly it is. I know there a easy job to do so would rather fit it myself than pay dealer prices. Merc dealer has said it will only take 20 mintues but still want best part of £250 to replace it. Thanks
     
  2. alexanderfoti

    alexanderfoti MBO Forum Supporter Authorised Forum Supporter

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    It's similar in style and location to the o2 sensor near the cat. On the left side of the engine.
     
  3. star

    star Forum Supporter Authorised Forum Supporter

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    There can sometimes be 3 “exhaust temp” sensors. Make sure you get the right one.
     
  4. OP
    Richard Stanton

    Richard Stanton Member

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    Thanks for the replies. I use a icarsoft mb V.20 and it says EGT bank 1 sensor 1.
     
  5. M80

    M80 Senior Member

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    I've 2 on mine, forward on the Cat and further down on the DPF.
    Best way is to monitor the readings on your iCarsoft and unplug. I've found faulty readings 'can' be -40 and +1,000 so if you can change the state of the faulty one by unplugging you've found it, if not changing the state of the healthy one means it's the other one.
     
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  6. steveq

    steveq Senior Member

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    Hi,

    I had P054615 and P208027 error codes on my 2011 W204 C220 a couple of years ago.
    I ended up replacing the Temp Sensor that is bolted into the exhaust manifold.
    I wrote it up here:-
    http://forums.mercedesclub.org.uk/index.php?threads/engine-warning-light.160527/#post-1588764

    As Martin says above, look at the actual temp values on your iCarsoft. The values shown on my i980 for that sensor were around 280degC even if the car was cold. If the value is the same as the coolant temp when the car is cold then there is nothing wrong with it and look elsewhere.

    The sensor cost me about €120 from an MB dealer.
    It certainly took me longer than 20 mins to fit. I ended up doing it twice (don't ask) and the second time I would guess at about an hour.
     
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  7. OP
    Richard Stanton

    Richard Stanton Member

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    Thanks for the responses, I will recheck in the morning when the engine is cold. I did a check the other day when the engine not so warm and the temp on EGT bank 1 sensor 1 was "270oC.
     
  8. M80

    M80 Senior Member

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    270 is a very reasonable reading. It'll reach that emp before the engine gets to 80+
    Why do you think it's a temp sensor?
     
  9. OP
    Richard Stanton

    Richard Stanton Member

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    It's come up as faulty on my icarsoft error P2080 after the car went into limp mode.
     
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  10. OP
    Richard Stanton

    Richard Stanton Member

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    Morning, I have just checked the EGT sensor whilst the engine is cold. I compared it to the coolant as you mentioned Steve. The coolant was 78 degrees and the EGT was 320 degrees, So from this I am pretty certain I need to change that sensor.
     
  11. steveq

    steveq Senior Member

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    Hi,
    If you coolant temp was 78deg then your car was almost up to normal temp.

    I was suggesting that you check the temp on the EGT when the car was cold but before you even started the engine. You will probably need the ignition switch to position 2 (i.e. just before the starter is engaged) to get a reading from the coolant temp or the EGT.

    Let's say that the coolant was at atmospheric temp (5 - 10 deg depending on where you are) then the EGT should show much the same if it is operating correctly.
    If it is still showing 320deg then it would suggest that it is faulty.
     
  12. OP
    Richard Stanton

    Richard Stanton Member

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    Hi, yes the engine was cold i did the check first thing this morning but I did start it up to do the temp check. The engine was probaly running about 1min whilst I ran the checks.
     
  13. steveq

    steveq Senior Member

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    Hi,
    Wow -- I would need to be driving for > 15 mins before my coolant got to that temp.

    Anyway, try it again before you actually start the car. When the engine is running the EGT sensor is subject to the hot gases immediately after they leave the cylinder head so the temperatures are very high pretty well immediately.

    The car doesn't need to be stone cold just not actually running and hasn't run for an hour or two. The EGT sensor should be very close in temp to the coolant.
     
  14. steveq

    steveq Senior Member

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    Hi,

    I just checked the EGT sensor values on my C220.
    I drove about 10 miles and then car had been parked for 40 mins.
    The coolant was at 78deg and the EGT sensor was showing 85deg.
     
  15. OP
    Richard Stanton

    Richard Stanton Member

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    Ok great thanks, I will try again in the morning.
     
  16. M80

    M80 Senior Member

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    Blimey, have you ckecked your sensor hasn't fallen out?
     
  17. steveq

    steveq Senior Member

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    ???
     
  18. M80

    M80 Senior Member

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    I only see egt's so low for a few seconds at start up, like you've said the temps rise rapidly, by the time the coolant is up the exhaust is 160 + (as it can cool when cruising w/o power). 235 to 400 is what I expect depending on my right foot needs.
     
  19. steveq

    steveq Senior Member

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    Ah, OK.
    I was measuring the EGT sensor when the engine was not running. It should be broadly aligned with the coolant temp (and the atmospheric temp when the car is cold). That way the range & accuracy can be measured.

    That's why I was suggesting that the OP checks it prior to starting the engine.
     
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  20. OP
    Richard Stanton

    Richard Stanton Member

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    Right, The car has been standing for 5 hours so the engine is pretty cold. Its 10oC outside at present. The coolant reading was again 78 so maybe that is faulty too unless its warmer under the bonnet. The EGT was showing 80, As soon as I fired the engine up within 15 seconds it said 330 degrees, the coolant was then up to 80 degrees.

    My fault P2080 EGT sensor only occurs if I properly give the car some hard accelaration then it goes into limp mode. When the code is cleared its fine again. My car is remapped to 250bhp also. As this is the code that keeps showing I may just get it changed and see what happens then.
     

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