Car won't restart in 169km Adblue

[Rjoseph692]

Hello. Last Friday I got a warning on the dash saying car won't start in 500km because of an adblue problem. I needed to go on a 300 km trip urgently so I toped up my adblue thinking it was that. I arrived home today, with 169km remaining. I will go tomorrow to my closest MB dealer, but the problem is that the dealer is 100km away. I don't have enough range left to make it back home.
If anyone knows why this is happening, please tell me ASAP. Any help is much apreciated!
Here are some photos:

 

[markjay]

This is likely to be a fault with the AdBlue system, possibly a faulty sensor in the AdBlue tank.

- Is there an independent specialist near you?

- Has the car been serviced by a Mercedes Benz dealer in the past 12 months? If so, then you have Mobilo cover and can call roadside assistance (and, if they deem the car to be undrivable, they'll pick it up on a recovery truck and deliver it to the nearest MB dealer).

- My understanding is that as long as you don't switch-off the engine, you can drive the car, so you should be OK with a trip to the dealer, but others will confirm (or call the dealer in the morning and ask them).

 

[markjay]

Also, if you're lucky, the dealer will erase the fault codes and that will be it.

But, if a repair to the AdBlue system is required, then sadly it will likely be neither quick nor cheap.

 

[Rjoseph692]

This is likely to be a fault with the AdBlue system, possibly a faulty sensor in the AdBlue tank.

- Is there an independent specialist near you?

- Has the car been serviced by a Mercedes Benz dealer in the past 12 months? If so, then you have Mobilo cover and can call roadside assistance (and, if they deem the car to be undrivable, they'll pick it up on a recovery truck and deliver it to the nearest MB dealer).

- My understanding is that as long as you don't switch-off the engine, you can drive the car, so you should be OK with a trip to the dealer, but others will confirm (or call the dealer in the morning and ask them).

So, either way I'm screwed. The car was in service at an certified Mercedes dealer, but not for any issues, just a regular B7 or A7 service (can't remember exactly), either way it was for replacing the transmission oil filter and transmission fluid. It was about 150 pounds, not cheap, especially from where I live. I can't believe that I'm having issues again. I heard a story recently of my friend going to change a clutch cable for a car and when he picked it up it said that he needed a new DPF. He went to a local mechanic and he said that it was 300% full. Maybe they did the same to me because I can't see why it throws issues at 150k km, with every service done in time. Either way I'm not going to that dealer because it is 300km away, the one I'm going to is much closer. If you want I'll update you with the exact diagnosis.
Thank you so much for your time!

 

[zipdip]

Adblue faults are a real problem when they pop up,the worst case is the tank needs changing and in this country you are looking at £1500 so given you had a service that included a gearbox service for £150 which would have cost at least £600 here the adblue tank might cost say £800 in your country,of course given wages may not be as high the repair is going to hurt.

 

[Rjoseph692]

Adblue faults are a real problem when they pop up,the worst case is the tank needs changing and in this country you are looking at £1500 so given you had a service that included a gearbox service for £150 which would have cost at least £600 here the adblue tank might cost say £800 in your country,of course given wages may not be as high the repair is going to hurt.

Thanks for replying! I meant to type 500~600 pounds, but at least know I that I didn't get scammed! I believe the adblue tank isn't leaking as I filled it to the brim 3 days ago and the car didn't move much since I came back home and there are no puddles or any obvious leaks that I could find. I am looking to do an adblue delete since it's cheaper than fixing all the potential problems that may arise with the adblue system. Have you had any issues with adblue?
Thanks for your time!

 

[markjay]

Thanks for replying! I meant to type 500~600 pounds, but at least know I that I didn't get scammed! I believe the adblue tank isn't leaking as I filled it to the brim 3 days ago and the car didn't move much since I came back home and there are no puddles or any obvious leaks that I could find. I am looking to do an adblue delete since it's cheaper than fixing all the potential problems that may arise with the adblue system. Have you had any issues with adblue?
Thanks for your time!

AdBlue is a complex system (MB calls it BlueTEC), unfortunately faults are common and repairs are expensive. 'AdBlue delete' would be illegal in the UK (and probably also in the EU) but some people still do it. In any event I suggest to try and erase the fault codes first (using STAR) and checking if they come back, the chances that this will fix the problem are not great but it's worth a try.

Also, as I said, if your car was serviced by a Mercedes dealer in the past 12 months then you are entitled to free Mobilo roadside assistance, they come out to you and they will try and diagnose the fault for you free of charge. But I am not sure what arrangements there are in Romania.

 

[Rjoseph692]

AdBlue is a complex system (MB calls it BlueTEC), unfortunately faults are common and repairs are expensive. 'AdBlue delete' would be illegal in the UK (and probably also in the EU) but some people still do it. In any event I suggest to try and erase the fault codes first (using STAR) and checking if they come back, the chances that this will fix the problem are not great but it's worth a try.

Also, as I said, if your car was serviced by a Mercedes dealer in the past 12 months then you are entitled to free Mobilo roadside assistance, they come out to you and they will try and diagnose the fault for you free of charge. But I am not sure what arrangements there are in Romania.

Yeah, that's the thing, I'm not sure if I'm entitled to Mobilo assistance. In about half hour I'm leaving for the dealer and I'm going to ask him about that. If it's worth your time you think maybe you can elaborate on that STAR thing? I'm guessing it's some kind of fault detector tool? Sorry for my lack of experience, but this is my first "new" car, I've only had cars from 2007 before this, and those things you could pretty much fix with a bit of wire and tape . On a sidenote I'm also thinking of buying a w204, for city driving or grocery shopping. I think it's a car that will age well, and I'm in love with the design!
I can't thank you enough for your time!

 

[markjay]

STAR is the Mercedes Benz diagnostic computer. The dealer will connect it to your car, and it will scan the car for faults. It can tell the dealer for example which sensor failed and needs replacing.

 

[Rjoseph692]

STAR is the Mercedes Benz diagnostic computer. The dealer will connect it to your car, and it will scan the car for faults. It can tell the dealer for example which sensor failed and needs replacing.

Good morning!
I'm at the dealer currently waiting for a diagnosis. From what he told me there is a NOx sensor shortage ATM. If the NOx sensors are at fault I should expect to pay some 500 pounds. The most expensive thing would cost 1300 pounds.

 

[Rjoseph692]

STAR is the Mercedes Benz diagnostic computer. The dealer will connect it to your car, and it will scan the car for faults. It can tell the dealer for example which sensor failed and needs replacing.

UPDATE:
The reservoir is at fault, they said they can't even reset the range countdown. I'll have to either go home in one go, and once I turn off the car get it to change the reservoir with a tow truck which will be another 1000 pounds or replace it now. Either way I'll have to pay ~1300 pounds to replace it. This is really upsetting.

 

[markjay]

UPDATE:
The reservoir is at fault, they said they can't even reset the range countdown. I'll have to either go home in one go, and once I turn off the car get it to change the reservoir with a tow truck which will be another 1000 pounds or replace it now. Either way I'll have to pay ~1300 pounds to replace it. This is really upsetting.

I believe the issue is with the level sensor in the reservoir, however Mercedes-Benz only sells the entire reservoir with the sensor.

Unfortunately, the entire AdBlue system is complicated, unreliable, and expensive to fix. You could try getting a second-hand unit from eBay (from any EU country - the German eBay should have quite a few), then get a local garage to fit the second-hand reservoir, or just move the sensor if possible. The main issue though will be that you will have no warranty and since this is a common fault, the new part may also fail in the future (in the UK, you get 2 years warranty for new parts fitted by the dealer). But in any case it will be much cheaper. To do this, you will need to have to hand the Mercedes-Benz part number of the replacement AdBlue reservoir - can you get this from the dealer before you leave?

 

[Rjoseph692]

I believe the issue is with the level sensor in the reservoir, however Mercedes-Benz only sells the entire reservoir with the sensor.

Unfortunately, the entire AdBlue system is complicated, unreliable, and expensive to fix. You could try getting a second-hand unit from eBay (from any EU country - the German eBay should have quite a few), then get a local garage to fit the second-hand reservoir, or just move the sensor if possible. The main issue though will be that you will have no warranty and since this is a common fault, the new part may also fail in the future (in the UK, you get 2 years warranty for new parts fitted by the dealer). But in any case it will be much cheaper. To do this, you will need to have to hand the Mercedes-Benz part number of the replacement AdBlue reservoir - can you get this from the dealer before you leave?

Thank you for the prompt reply. I will inquire the dealer about this sensor but unfortunately I already left. He said he had no adblue tanks available and that I should go home and wait for him to call. I left the dealer with 41 km of range left and about 10-15 minutes later the message disappeared. I thought I accidentally quit out of it but when I went in the service menu it didn't appear either. I'm now going home and I'm not going to stop the engine until I arrive because maybe it won't start again.
I really appreciate you man you were of much help.

 

[Smiley]

Problems with the adblue system are far too common. The problems occur because of problems with either the NoX sensors or the sensor in the adblue tank. MB could have designed the system and set a pricing strategy to make the system relatively cheap to maintain. But they didn't; it is the opposite. I mean why design the sensor in the tank so that you have to buy a new tank at a huge cost - how can a tank cost about £1000? The icing on the cake is that the expensive parts are not even available......
It is hardly surprising that owners of these cars are finding innovative ways to completely delete the adblue system.
Unless you really want to drive a newer car you are better off with a 2003-2007 pre DPF pre adblue car. Or if you want real simple a 1990s w124!

 

[Rjoseph692]

Problems with the adblue system are far too common. The problems occur because of problems with either the NoX sensors or the sensor in the adblue tank. MB could have designed the system and set a pricing strategy to make the system relatively cheap to maintain. But they didn't; it is the opposite. I mean why design the sensor in the tank so that you have to buy a new tank at a huge cost - how can a tank cost about £1000? The icing on the cake is that the expensive parts are not even available......
It is hardly surprising that owners of these cars are finding innovative ways to completely delete the adblue system.
Unless you really want to drive a newer car you are better off with a 2003-2007 pre DPF pre adblue car. Or if you want real simple a 1990s w124!

Had a couple cars from that era. A 2003 model and a 2007. Not going to say which make because maybe I'll get banned but anyway. I needed to replace the timing belt on the 2007 car. It was 30k km past it's service date. When I started the car it ran horribly and then it snapped. It was super cold outside so I'm guessing the rubber was also very stiff. The mechanic said that the only thing that saved my car that date was the engineering of the engine so that when it idles there isn't much overlap between the piston and the valves. Anyway, coming back to what you said; The dealer said that the actual tank wasn't leaking and as @markjay said, it's the liquid level sensor that's gone bad. I can't possibly understand what's costing 1000 pounds+ for a tub of plastic with a sensor in it. With this said I'm looking for someone to code the adblue system off. I'll ask him if it's possible to turn on and off at will(which I'm guessing it is) in case the rozzers catch me. All this aside, if you know anywhere where I could get aftermarket parts for this please let me know!
Thank you for pitching in man!

 

[Rjoseph692]

Quick update:

The car seems to start without problems even though it shouldn't have. I'm not complaining . Either way, I had my dad ask around for this type of thing and he found a guy that had the same problem, only his message disappeared at 130km left of range. He drove it problem free until his engine stopped at a stoplight because of the start-stop system and when he pressed the accelerator the car refused to start because of the adblue issue. I hope this doesn't happen to be, but if it does, I'll let you know!
Huge thanks to everyone who replied

 

[merc estate]

Thanks for letting us all know about this, keep us updated, they are a lot of people driving around with there fingers crossed

 

[markjay]

Quick update:

The car seems to start without problems even though it shouldn't have. I'm not complaining . Either way, I had my dad ask around for this type of thing and he found a guy that had the same problem, only his message disappeared at 130km left of range. He drove it problem free until his engine stopped at a stoplight because of the start-stop system and when he pressed the accelerator the car refused to start because of the adblue issue. I hope this doesn't happen to be, but if it does, I'll let you know!
Huge thanks to everyone who replied

Remember to turn off ECO at the start of every journey...

 

[grober]

First sensors were twin electrode design and the liquid level was sensed by the resistance of the liquid between two electrodes. The later design uses an ultrasonic sensor embedded in the base of the tank. It measures the level by a reflectance signal bounced back from the surface of the adblu liquid. Being water-based the entire system is extremely sensitive to temperature with the urea crystallising out of solution and generally contaminating the system.

 

[Smiley]

First sensors were twin electrode design and the liquid level was sensed by the resistance of the liquid between two electrodes. The later design uses an ultrasonic sensor embedded in the base of the tank. It measures the level by a reflectance signal bounced back from the surface of the adblu liquid. Being water-based the entire system is extremely sensitive to temperature with the urea crystallising out of solution and generally contaminating the system.

Thanks for the explanation Grober. To sum up - an over complicated design without a single thought by the design team of the ongoing cost effective maintenance of the car. Well done MB.