Sorry - Another Adblue Issue

[IDT2025]

Hi New here so treat me gently. I have a 2016 C220 with150k on the clock and a great car it has been. Until now. I have entered the adblue stage it seems. Late 2023 I had NOX sensor warnings and had them changed by MB under an outstanding recall. Between then and January this year no issues but the car was left on the drive for periods of 3, 2 and 1 month (which I guess has caused what I am about to describe). I now have the adblue issues. Started with the engine management light followed by the 'engine wont start in..' message. Checked the adblue level and it had the 'cannot measure' warning. Whilst I thought there was a half a tank I assumed it was wrong and it was empty and put more in - overfilling it (though I didn't realize this may have had consequences). I cleared the fault codes and expected no further issues. The lights and warnings quickly came back on and I read these forums to find the reality of the situation. For a period I was able to reset the codes (I use a very basic OBD system) whilst I read more and decided what to do. At one point the adblue level was also read. I also added Forte anti crystal to the tank.

I have now cleaned the sensor (which was solid and with no hole at all to let even small amounts of adblue through) and have no codes but the adblue level still reports that it cannot be read. More importantly despite there being no codes the message saying engine wont start in.. is still there.

So I now have a lump of metal in the drive with 200 miles left. I am now aware of the host of issues with Adblue but need to be able to sort something out to be able to get rid of the car (other than as scrap which would be a great shame as, despite the mileage, it is in otherwise great shape). I am uneasy about deleting the adblue but that may be the last (but one) resort.

My questions are: Is there a way of removing the 'Engine wont start in..' message - even short term? I tried disconnecting the battery to no avail. To do any work on the car I will need to move it so need 'more' miles. There are no codes showing and the message remains.

Could the overfill be causing a problem, should I drain the tank and what is the best way of doing this? There seems to be an anti syphon device when I have tried to put a pipe in. As above, I am loathe to move the car with a small number of miles left.

Can anyone recommend an indie in the South Wales/West area that has expertise in these problems? I use a good indie but they insist on using new MB parts only which I am worried may push the price up if it comes to a new adblue tank (bearing in mind I will probably get rid of the car ASAP).

Thanks in advance and apologies for another adblue post!

 

[Bigdrew]

Hi did the car ever have s adblue delete

 

[toteimerced]

You try a used tank from eBay or somewhere, a new one is something like £1300, it might cure your problem, or as you said AdBlue solution delete, which is illegal though.

 

[IDT2025]

Thank you for your replies. The car has never had an adblue delete - the only 'non consumable' ever changed were the NOX sensors in 2023 - just before the car was left idle for the first time.

I will look at a used tank though my problem is that I have to take to car away to work on it and there are limited miles left. If the tank fails to fix the problem then obviously less mileage to play with. I have reset the codes and removed the 'Miles' warning but now I cannot - presumably because there is no code showing.

I am happy to at least try other solutions but need to be able to move the car to try them so removing ( or at least resetting) the miles warning is my issue at the moment.

The delete worries me but I will do it but preferably as a last resort.

 

[Bigdrew]

You try a used tank from eBay or somewhere, a new one is something like £1300, it might cure your problem, or as you said AdBlue solution delete, which is illegal though.

The problem you have I would think is the pump in the tank but unfortunately you cannot buy the pump separately you have to buy the pump and the tank together but that might be quite expensive the only other option which would solve the problem is adblue delete which is illegal which alot of people have done and probably cheaper

 

[IDT2025]

Thank you, I am starting to think a delete may be worth it.

I am though puzzled why the 'Engine wont start' message is there even though no codes are showing.

 

[Bigdrew]

Thank you, I am starting to think a delete may be worth it.

I am though puzzled why the 'Engine wont start' message is there even though no codes are showing.

Hi what message is it saying when you check the adblue

 

[IDT2025]

It says 'Cannot measure level'. I know there is plenty in there - I overfilled it when the problem first arose thinking it was empty which could be contributing to the problems.

The sensor has been cleaned out. There are no codes and the 'Engine Will not Start in' message is on.

What my plan had been was to drain the tank next and flush it through but there seems to be an anti syphon device? or at least I cant get a tube into the fluid. As a result I need to move the car to a place I can work on it but cannot with limited mileage on it.

As matter of interest, can the adblue crystallize in the tubes or only when exposed to oxygen?

 

[Bigdrew]

Hi what message is it saying when you check the adblue

Just noticed you had the cannot measure message

 

[W1ghty]

Long thread from the other forum about pump replacement

w213 adblue pump and engine not start

Could it be that the AdBlue system in my car was programmed by the previous owner, and now, for some reason, it's throwing an error? I keep clearing the error, and I've already driven about 2,000 km without any notifications that you have left a certain distance before engine not start. The...

forums.mercedesclub.org.uk

 

[Bigdrew]

Hi you said that you over filled it with adblue which can sometimes damage ultrasonic sensors and the wiring

 

[markjay]

Your issue seems somewhat similar to this one:

Post in thread 'Adblue'

Feb 25, 2025

Hi all as I said before car went in to Mercedes for some recall on Thursday replaced two nox sensors today went back in for the updates that they couldn’t do on Thursday so left it with them so far so good got a call early on in the afternoon to say it was ready no problem until I started the car and engine management light on so went back in and they got somebody to check it there was never anything engine management light on before the only thing was the adblue never showed any level now the adblue says cannot measure level never had this until the upgrade now there saying it can’t be...

• Bigdrew

 

[Bigdrew]

Your issue seems somewhat similar to this one:

Post in thread 'Adblue'

Feb 25, 2025

Hi all as I said before car went in to Mercedes for some recall on Thursday replaced two nox sensors today went back in for the updates that they couldn’t do on Thursday so left it with them so far so good got a call early on in the afternoon to say it was ready no problem until I started the car and engine management light on so went back in and they got somebody to check it there was never anything engine management light on before the only thing was the adblue never showed any level now the adblue says cannot measure level never had this until the upgrade now there saying it can’t be...

• Bigdrew

Yes but I never over filled mine with adblue

 

[markjay]

Yes but I never over filled mine with adblue

Same error message, following replacement of the NOx sensor under recall...

 

[Bigdrew]

Same error message, following replacement of the NOx sensor under recall...

Yes but mine happened the same day on the recall I don’t think his did

 

[IDT2025]

That is correct. The NOX sensors were changed in 2023 and caused no obvious issues at that time. I then had to work overseas for a 3 spells of 3,2 and 1 month (which I think was partly the cause of the issue). The sequence was that the management light came on, then the 'Engine will not start message supposedly because the adblue level was low. I thought it was reasonably full but believed the message and tried to put 10L in only for it to overtop.

I checked and cleared the codes and all was good for 30 miles and everything came back. Since then the codes will clear and the mileage counter goes away for 30 miles but the 'cant measure' message remains.

I have cleaned the sensors (which were absolutely choked with crystallized adblue) but now I cannot reset the mileage message even though no codes are showing - that is my immediate problem as I cannot move the car to a place where I can work on it. My plan is to drain and flush the adblue tank before either swapping the tank with a used one or as an absolute last resort deleting the adblue.

Anyone know how I might clear the 'engine not start' message? Also is the pump able to be changed without changing the tank? I know the sensor inside cannot be.

Thanks everyone for you continued advice.

 

[Bigdrew]

That is correct. The NOX sensors were changed in 2023 and caused no obvious issues at that time. I then had to work overseas for a 3 spells of 3,2 and 1 month (which I think was partly the cause of the issue). The sequence was that the management light came on, then the 'Engine will not start message supposedly because the adblue level was low. I thought it was reasonably full but believed the message and tried to put 10L in only for it to overtop.

I checked and cleared the codes and all was good for 30 miles and everything came back. Since then the codes will clear and the mileage counter goes away for 30 miles but the 'cant measure' message remains.

I have cleaned the sensors (which were absolutely choked with crystallized adblue) but now I cannot reset the mileage message even though no codes are showing - that is my immediate problem as I cannot move the car to a place where I can work on it. My plan is to drain and flush the adblue tank before either swapping the tank with a used one or as an absolute last resort deleting the adblue.

Anyone know how I might clear the 'engine not start' message? Also is the pump able to be changed without changing the tank? I know the sensor inside cannot be.

Thanks everyone for you continued advice.

Hi don’t think you can replace the pump itself self I think you have to buy the pump and tank together but but I may be wrong

 

[IDT2025]

Thanks. Am I correct in thinking there is an anti-syphon device on the adblue tank and it has to be drained?

 

[Seanalf]

That is correct. The NOX sensors were changed in 2023 and caused no obvious issues at that time. I then had to work overseas for a 3 spells of 3,2 and 1 month (which I think was partly the cause of the issue). The sequence was that the management light came on, then the 'Engine will not start message supposedly because the adblue level was low. I thought it was reasonably full but believed the message and tried to put 10L in only for it to overtop.

I checked and cleared the codes and all was good for 30 miles and everything came back. Since then the codes will clear and the mileage counter goes away for 30 miles but the 'cant measure' message remains.

I have cleaned the sensors (which were absolutely choked with crystallized adblue) but now I cannot reset the mileage message even though no codes are showing - that is my immediate problem as I cannot move the car to a place where I can work on it. My plan is to drain and flush the adblue tank before either swapping the tank with a used one or as an absolute last resort deleting the adblue.

Anyone know how I might clear the 'engine not start' message? Also is the pump able to be changed without changing the tank? I know the sensor inside cannot be.

Thanks everyone for you continued advice.

Interesting, where were the sensors and how easy to get to them? I thinking preventative measures for others

 

[IDT2025]

HI The NOX sensors were changed at the dealer under a recall that had never reached me (though it seems that some dealers are changing them as a 'gesture').

The adblue sensor (assuming my description is correct) is reasonably easy to access. Remove 2 covers and the sensor enters the exhaust more or less level with the drivers seat (RHD)

My main issue now is how to clear the 'engine wont start' message whilst no code is showing. I use a very basic ODB block with Torque and no code appears so the message cannot clear.

Also, can you change the adblue pump without changing the tank. I know the level sensor is integral but is the pump?