Exhaust Gas Temperature Sensor P2080 Merc W204 C250 Cdi

LostKiwi

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The only time the EGT should not be in triple digits is when starting from cold.
It shouldn't track coolant temperature at all. Exhaust gases by their very nature are hot, very hot. That's why a turbo glows red when given serious grief.
 

alexanderfoti

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Also a coolant temp of 78 after 5 hours indicates that you coolant temp sensor is faulty or the code reader is giving incorrect values.
 
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Morning, So this morning I have completed the check again as advised by Steve. The outside temp is 10 which is 50 in oF, The coolant temp was 48oF and the EGT sensor was bang on at 50oF. So all look correct on that scale. As soon I fired up the engine monitoring the live data stream, I counted to 15 and within that time the Egt sensor B19/11 was reading 360oF, The coolant up to 50oF. So my thought is yes the egt will heat up quickly but surely the sensor should'nt be reading that hot within 15 seconds especially if as Steve said his does'nt read that hot.
My thinking is as it goes into limp mode under heavy accelaration and this is showing up as the faulty part then it needs changing. As far as I'm aware the EGT has an effect on the torque etc thats delivered to the engine which would explain my situation.
 

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EGT at 180 C within 15 seconds doesn't seems ok to me. I'll check later when I go out, but maybe you need to look elswhere for your problem.
As a 2012 model you'll surely have a DPF, what about the other temperature sensor?

I find Torque (free) on an Android device, fed by a cheapo BT sender is good for monitoring on the go.
 

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Hi,
It did cross my mind that you could be reporting Farenheit and we are talking about Centigrade/Celcius.
360degF is about 182degC which, as Martin says, looks correct.
When mine went faulty it showed about 280degC constantly even when the car was cold and the engine not running.
 

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The only time the EGT should not be in triple digits is when starting from cold.
It shouldn't track coolant temperature at all. Exhaust gases by their very nature are hot, very hot. That's why a turbo glows red when given serious grief.
I am not saying that it tracks the coolant temp when the car is running. It does track it when the car is cold and not running.
I just checked mine now. The outside temp is 10degC, the coolant was showing 10degC and the EGT sensor was showing 10degC.of course the car wasn't running.
It just shows that the EGT sensor is changing and accurately reflecting the temp.
 
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I've changed my icarsoft to celcius now and it reads 10 degress cold as reflecting the coolant temp. When I run the car it increases very quickly to 180 degrees. If this is normal then any suggestions why when it goes into limp mode it gives P2080 which is the egt sensor and says its the sensor 1 bank 1 which is the B19/11.
 

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As an inline 4 I always assume it would be the 1 bank.
I would attempt to interogate the other temp sensor,
just a thought but might the other sensor being reading out of spec but the iCarsoft is picking up a problem between the 2 readings?

Truth is I'm not impressed with iCarsoft, it has its uses but I question its reliabilty.
 
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They both read around the same temps.
It was my other obd2 reader which identified the EGT sensor as being faulty. I might try and get the car to replicate the limp mode and then attach the icarsoft to see what the readings are. Its not done it for a week or so but I haven't been hammering it. I did notice that everytime I floored it there was a lot of black smoke coming out of the exhaust which seem to continue as long as my foot was on the floor, I didn't think that happened with a DPF. The DPF seems to be running fine, the icar is saying its at 41% fill level with only 1g of soot. I was condsidering forcing a DPF regen and taking it for a blast.
My icarsoft is the MB v2.0 the latest one and seems pretty good to be fair.

My only other thought was I've heard the W204 C250cdi doesnt repsond well to being remapped, Wondered whether this would cause an issue but the mechanic at my local mercedes specialist didnt seem to think so.
 

alexanderfoti

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My only other thought was I've heard the W204 C250cdi doesnt repsond well to being remapped, Wondered whether this would cause an issue but the mechanic at my local mercedes specialist didnt seem to think so.

The cause of limp needs to be investigated properly, but a good mapper can map these engines without issues.
 
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Ok not sure what the thoughts are but I did some live data monitoring on the sensors today. I drove around 10 miles and then stopped, The EGT sensor 1 was showing between 130-170 dregrees celciuis, However when driving was fluctuating massively, If I accelarated it would go upto as much as 440oC and then back to 130oC then stable between 130-170 but as soon as I accelarated back up into the high 300's and into the 400's. Is this normal?
 

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Yep, normal, although unless coasting I would have expected higher than 130, but mine is heavier with a larger engine - so more hot gasses.

If you think the temperature under load is 400, flippin' hot compared to an ambient of say 12, it will lose that temperature to the outside pretty fast.
 
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garethbevan59

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Guys I also have the same etc p2080 can anyone tell me which one as Merc says I have two fitted on my car 1. Upstream of dpf 2. Upstream of turbo? My car is x218 CLS 250 cdi om651 - I have bought a icarsoft mbv2 and can read the codes and erase thanks the part number I keep getting for this sensor is
A0081532228 does anyone know if it's easy to change and if it's the correct part number? Sorry for thread hi jack
 

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alexanderfoti

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Bank 1 sensor 1 is upstream

New sensor needs to be taught in with Xentry and and software potentially updated as well.
 

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Hi Gareth and welcome,

I suggest that you go through the steps suggested further up this thread -- that is to look at the actual temperatures shown by the EGT when the car is cold and not running. The values should be the same as the coolant and the ambient temperature.

When the car is started the values should shoot up pretty instantly to > 150degC.

When I replaced mine I didn't have to 'teach' the car -- maybe I was lust lucky?
 

garethbevan59

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Thanks Steve I'll review and take a look

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garethbevan59

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Hi Gareth and welcome,

I suggest that you go through the steps suggested further up this thread -- that is to look at the actual temperatures shown by the EGT when the car is cold and not running. The values should be the same as the coolant and the ambient temperature.

When the car is started the values should shoot up pretty instantly to > 150degC.

When I replaced mine I didn't have to 'teach' the car -- maybe I was lust lucky?
Hi Steve although the car was at normal operating temps I want to make sure I'm looking at the right values, so am I looking at engine coolant temperature and catayst temp b1-s1 ? When car is cold these should match right?
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steveq

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Hi,

I don't think that the Catalyst Temp is the correct sensor.
The sensor is the one Upstream of the Turbo and is called B19/11.
I don't have a MB V2 OBD reader and have the older i980 with the smaller display. I presume the menus are different.
I will look to see where the B19/11 sensor is displayed on the i980 which might be in a similar location but that could be tomorrow.
 

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Hi,
I checked where the EGT sensor values are displayed on my i980 OBD reader.
It is on the menu item that shows the Diesel Particulate Filter values.
There are many values shown and the B19/11 temp values is on the third screen.
On my i980 it says that it is upstream of the DPF (which is true) but there are 2 sensors with the same description. The B19/11 is actually upstream of the turbo.

I have noticed that there are a number of values that have the incorrect description, e.g. the "Distance since the last DPF clean" is actually the odometer reading in Kms.
 
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