Hi, does anyone know where I can locate EGT sensor 1? I know where 2, 3 and 4 are. Thank you

Andy

2 hours ago, Rollie said:

Hi, does anyone know where I can locate EGT sensor 1? I know where 2, 3 and 4 are. Thank you

Andy

Hi I think you will find the sensor you have marked three is actually number one as its at the beginning of the exhaust stream next to the adblue the others run downstream.

Steve.

Thanks Stevey 

I’ll double check but I’m sure when I disconnected it then ran the diagnostic number 3 sensor came up. I do hope your right as that will be easy to do. Thanks again

Unfortunately it’s defo sensor 3 by the looks of it when I’ve doubled checked. 
any other help would be appreciated 

cheers

Andy

6 hours ago, Rollie said:

Unfortunately it’s defo sensor 3 by the looks of it when I’ve doubled checked. 
any other help would be appreciated 

cheers

Andy

Hi in that case it could be the one underneath as the exhaust goes under the bulkhead, weird thing is on my VCDS when mine started acting up it was the top first sensor that I changed, the one further down the pipe is a sod to get to.

Steve.

Hi Steve,
 

The one further down the exhaust is sensor 4, for the life of me I can't see where sensor 1 is. Don't suppose you have any plans lol where it's located. I've booked it into the garage but have to wait until 17th April 🤦🏻‍♂️😫. Typical it can't be the simplest one, that's cars for you. 
 

Thanks for your help
Andy

8 hours ago, Rollie said:

Hi Steve,
 

The one further down the exhaust is sensor 4, for the life of me I can't see where sensor 1 is. Don't suppose you have any plans lol where it's located. I've booked it into the garage but have to wait until 17th April 🤦🏻‍♂️😫. Typical it can't be the simplest one, that's cars for you. 
 

Thanks for your help
Andy

Hi got a new microcat coming Tuesday I will have a look on that and see if I can get a schematic diagram.

Steve.

Thanks Steve, appreciated 

On 4/1/2024 at 5:37 PM, Rollie said:

Thanks Steve, appreciated 

Hi Andrew please find what I have discovered, there are only three sensors not four and I pretty certain that the diagnostics you are using is what's at fault, each platform relies heavily on the software writers interpretation of a fault and through experience with different platforms I have come to the con elusion they must have had a few beers whilst writing the software. 

Steve.

Steve,
 

I didn't know that about the software. I've just bought one which is cheap to be honest called Carista. Thanks for the info I'll buy the sensor you suggested as per diagram and see what happens. Will keep you informed 

Thanks

Andy

23 hours ago, Rollie said:

Steve,
 

I didn't know that about the software. I've just bought one which is cheap to be honest called Carista. Thanks for the info I'll buy the sensor you suggested as per diagram and see what happens. Will keep you informed 

Thanks

Andy

Hi Andy, used loads of peoples differing software and found shall we say quite a few variations on codes the cheaper they get the more lethal they become bit of a minefield really that was why a few years ago I bought VCDS, that definitely nailed it every time, in saying that the new cab I have is a VW Passat and my VCDS wont go near it as everything is protected by the new SFD system, I wont go in to any detail because its long and boring but suffice to say that post 2020 you can't do a blasted thing on the car without having the right system, thats when I bit the bullit and bought OBD Eleven pro, yes you have to buy tokens to perform some functions but its about as as good as VCDS but without the hefty price tag, VCDS latest multi vin software is nearly £700 but OBD came in at £104 with a token bundle its a lot slower scanning as its bluetooth but it gets there and gets you what you need, the diagrams are from my new system, the good news is the part number for all three is the same.

Steve.

Hi everyone,I'm having the same problem on my A6 ultra 2014, bank 1 sensor 1. I've bought a new one and replaced it as Andy is showing on picture (S3) becauseinwas told that was the one...issue still present.

 Disconnected the other one (brown plug) no difference but as soon as I disconnected the 3rd one,the one that is sitting at the bottom, the glow plug light started flashing straight away and error couldn't be deleted so I'm guessing that's the sensor 1 but not sure.

 You guys have any ideas or do you think that's the correct one? TIA

Raul

Edited September 25, 2025Sep 25 by Raul DS

18 hours ago, Raul DS said:

Hi everyone,I'm having the same problem on my A6 ultra 2014, bank 1 sensor 1. I've bought a new one and replaced it as Andy is showing on picture (S3) becauseinwas told that was the one...issue still present.

 Disconnected the other one (brown plug) no difference but as soon as I disconnected the 3rd one,the one that is sitting at the bottom, the glow plug light started flashing straight away and error couldn't be deleted so I'm guessing that's the sensor 1 but not sure.

 You guys have any ideas or do you think that's the correct one? TIA

Raul

Hi the anomaly with this is that sometimes it will show bank 1 because bank 3 is not suppling the correct information to bank 1 sometimes it is bank 1 but I normally always suspect bank 3 as this has the hardest life in the system you did the right thing pulling the plugs but if you have a reasonable diagnostic platform you can check the temp on each sensor in line and its usually the sensor that reads nowhere near the other two thats duff, I have even had it where the last sensor is reading -70 degrees, really!! the check for temp is available in the live data and if as you say one sensor made no difference I would assume thats the one.

Steve.

Steve.

Hi Steve and thanks for the reply.

I don't know what's going. Today checked again and both sensors on top showed the same error,same as the one underneath.I'll try again and check the temperature like you're saying...this is driving me nuts!

Once again thank you for the reply,much appreciated.

Raul

22 minutes ago, Raul DS said:

Hi Steve and thanks for the reply.

I don't know what's going. Today checked again and both sensors on top showed the same error,same as the one underneath.I'll try again and check the temperature like you're saying...this is driving me nuts!

Once again thank you for the reply,much appreciated.

Raul

Hi EGT sensors are very sensitive  but the only way is to check their temp figures whilst running, chances are if you have a fair amount of milage and age they are all pretty weak, often asked how long an EGT lasts?,

 

 

how long is a piece of string, just keep your mind focused on the real time readings on each sensor that will give you the answer.

Steve.

Thank you very much Steve,really appreciated.

 Will work 4 days now so I'll concentrate on it on Wednesday then will let you know.

Cheers

Raul

Hi Steve,sorry for the late reply.

Yesterday was crazy busy trying to sort car out but the good news is it's fixed!!

I think i saw here in this topic someone saying there's only 3 sensors but in fact it's 4. The 2 on the top close to the lambda sensor and nox,one that comes straight up at the bottom(orange plug) and yesterday saw another one underneath the turbo if I'm not mistaken( black plug).

 Bought a new sensor(black plug) and tried it on that plug and no error whatsoever and since I had bought one a few months ago and the shape and plug being exactly the same I just used it and no errors,no lights,nothing all day!! Returned the sensor and saved £57!!

Thanks for your support and replies,very much appreciated.

Raul 

Edited October 3, 2025Oct 3 by Raul DS

Raul, what were the symptoms behind you needing to resolve this issue please. 

I have an ongoing DPF issue where temperature keeps dropping during a regen and I suspect what you've found.

Many Thanks

6 hours ago, Speedsailz said:

Raul, what were the symptoms behind you needing to resolve this issue please. 

I have an ongoing DPF issue where temperature keeps dropping during a regen and I suspect what you've found.

Many Thanks

Hi the only way to find out is monitor the temps on the EGT sensors on live data, if you don't have that facility the only other way is to replace the lot the temp drop is due to a faulty sensor showing the wrong temp to the ECU which will interrupt the regenerations.

Steve.

9 minutes ago, Stevey Y said:

Hi the only way to find out is monitor the temps on the EGT sensors on live data, if you don't have that facility the only other way is to replace the lot the temp drop is due to a faulty sensor showing the wrong temp to the ECU which will interrupt the regenerations.

Steve.

Yes understood, if you monitor the live data how do you know if its correct or false? My inlet and outlet temperatures look sensible. a graph is attached. I can get a DPF inlet temp of 630 and Outlet at the same time round about 506, but then it drops back off again, and I have to try and get back up with loading the engine. So the whole regen can take me 70 miles or so whereas it should stay at 600+ and get it done asap and burnt the soot off. I don't have one single DTC. Appreciate the help

20 minutes ago, Speedsailz said:

Yes understood, if you monitor the live data how do you know if its correct or false? My inlet and outlet temperatures look sensible. a graph is attached. I can get a DPF inlet temp of 630 and Outlet at the same time round about 506, but then it drops back off again, and I have to try and get back up with loading the engine. So the whole regen can take me 70 miles or so whereas it should stay at 600+ and get it done asap and burnt the soot off. I don't have one single DTC. Appreciate the help

Hi 630 is right for the inlet but 506 is not even close unless its a Fiat 500 with a Cordierite cored DPF, no you won't get a DTC until the DPF is blocked, would suggest changing the downstream sensor, should realistically take about five miles to do a standard regen, also monitor soot levels the measured being themes important along with the ash, the calculated soot is done by an algorithm  which will always run higher than the measured this kicks off the regen earlier which prevents the soot accumulation on the measured soot from getting to high, the trick bit is the last part of the regen when measured soot is lower but the calculated is to high but reduces during the last minutes of the cooling [fan going].

Steve.

Thanks for the reply,

before I go ahead and swap out the outlet temp sensor... it was ref your comment on soot levels. one strange observation I see is that the soot mass calculated can be over 24g (triggering regen) but the soot mass calculated only ever sits as a max 5g. Then during the regen towards the end when the calculated gets to 17.77g the measured starts to go minus numbers. Does that give any more clues? TIA I can attach a log if it helps

8 hours ago, Speedsailz said:

Thanks for the reply,

before I go ahead and swap out the outlet temp sensor... it was ref your comment on soot levels. one strange observation I see is that the soot mass calculated can be over 24g (triggering regen) but the soot mass calculated only ever sits as a max 5g. Then during the regen towards the end when the calculated gets to 17.77g the measured starts to go minus numbers. Does that give any more clues? TIA I can attach a log if it helps

Hi as I said the calculated is a algorithm which is based on a sum that the ECU does the measured going minus is fine but the calculated will always be higher but drops during the last cooling stage and the measured stays stable as the calculated drops, I would be more interested in the ash loadings, if the ash is high that only leaves a smaller accumulation are for soot and often as not high ash causes longer regens where its trying to burn out ash which it can't do, ideally when in regen mode the EGTs should register around 650 to burn efficiently, also check your DPF pressure sensor when running ideally it should be about 2-3 psi rising to 7psi when revved, if its higher on idle your DPF is blocked or the sensor is faulty.

Steve.