Exhaust Gas Temperature Sensor P2080 Merc W204 C250 Cdi

[garethbevan59]

Hi Steve yes I started a new thread as I was able to compare the values from the two sensors however nothing strange from what I can see, I done the test whilst cold then again at running temp car still gives P2080 albeit pending and a simple on off of key fixes it but I'd rather fix properly

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[steveq]

Those values look very plausible and correct.

I suggest that you clear the fault using the MB v2.0 and then see if it returns.
If (When) it returns you should look at the values of the sensors at that time.

By the way, on my i980 the description of the sensors are the same but the name is different, i.e. one is called B19/11 and the other is B19/9.
Your MB V2 seems to be naming both the temp sensor upstream of the DPF and the temp sensor upstream of the turbo as the B19/11?

 

[Iain Greig]

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

Just done one on my C250cdi , a bit fiddly to get cable routed. Only use genuine MB sensor. Start to finish 2 hrs. Remove air filter box to get at bank 1 sensor screwed into exhaust manifold. 17mm.

 

[Fergal Phelan]

Hi all, first time posting here.

I've had this same code p2080 coming up intermittently. Took it to the mechanic and he said the B1S1 was reading fine and there was signs of it being replaced already as there were new cable ties on the wiring. He reset it and it came back in a few days later, I left it as he was busy and it led to the DPF getting blocked. He cleaned it out and forced a regen, cleared the fault and it stayed away for a few days again. I've been clearing it with a cheap diagnostic reader I got from Amazon since. I cant get a live reading on B1S1 with the cheap unit, but I can get a reading from B1S2. This went as high as 700 degrees C one day while motorway driving, would this happen during a regen. I monitored it today while doing local driving, it was 10 degrees C on startup, rose to about 400 deg C within 1K, and stayed steady around this, is this normal?
Where does the P2080 code come from, does the ecu compare the readings between both sensor and give a fault if they are not in the same region.
I'm sort of hoping that B1S2 is faulty as it is a quarter the price of B1S2, 100 compared to 400.

Sorry for the long winded post, any help would be appreciated, thanks.

 

[alexanderfoti]

You need the whole code definition on xentry as it's not just:

Whether the sensor is open circuit or short circuit
Whether the sensor is reading too low vs engine load or too high
Whether the sensor is stuck on one value

Its also comparing upstream and downstream values vs calculated exhaust gas temperatures based on engine load and speed

So reading the freeze frame data at time of the fault is important to figure out why it's complaining about the sensor