V Strange adblue Urea symptoms help

[Ck111]

Hi all. Il try and keep this as short as possible.
Its a 2015 c4 grand picasso.
Adblue light was randomly coming on showing 1500 miles left, this went on for about 6-8 months. always 1500 miles left, this never changed. I could start the car and it would go away for weeks, etc then just totally randomly show up again, 1500 miles left to top up. The First time it happened i went to fill the tank only to discover it was already full.
I could hear what i think is the pump in the boot area, at various times trying to pump the adblue, but the level always stayed full.
A few weeks back the service light, engine fault light started to come on with the urea light, much more frequent now compared to before, but still the tank is full and 1500 miles to top up and would randomly go out and then return again.
Now the weird thing is yesterday the same warning lights again but this time 700 miles to top up and by the time i had finished the journey it gad dropped to 650 miles, which has never happened before.
I got the lend of a topdon scanner and when i scanned the car, the previous owner must have 'turned of' the adblue or got it mapped out or whatever, as its showing as adblue not present or along those lines of wording when scanned.
Any ideas If it was turned of, then why is it starting to countdown and show warnings now?

[RichardW]

You might need to try a different scanner - it may be that the ECU has gone off line, which is why it can't talk to it.

[GiveMeABreak]

Bear in mind that the 1500 mile limit will stay like this all the time. It only reduces and counts down when the actual Adblue in the tank is at the 1500 mile range.

The pump noise you can hear after stopping the vehicle is generally the reversing of the pump, to suck the adblue back out of the supply pipe into the tank to prevent crystallisation.

Your issue is that somebody has intervened with it diagnostically and tried to delete the system most likely so it's in a poor state. I would get it properly looked at and put back to how it should be or you are going to have problems. Of course we don't support any emissions crippling here, so can't really help with a system that has had this intervention as we can't say what has been done exactly or what settings have been changed.

The Adblue system is not operating correctly as a result of whatever has been done, so is not pumping Adblue, which is why the tank is full. I suggest you bite the bullet and get a dealer to re-download the ECU settings for you and check the system out properly. Once they've done that, hopefully it will be back to normal.

[wheeler]

I would imagine that if the adblue had been mapped out you wouldn’t be getting any issues with warnings about it, more likely the scanner you are using is not compatible with the system.

[GiveMeABreak]

I suppose it depends on the model of the Topdon - which do range considerably in capabilities / price.

[Ck111]

Yea i found it really strange that if it had been mapped out before i bought the car ( over a year ago ) then why just now has it decided to actually start a countdown which started at 700 miles , then moved onto 650 miles, which later this week in theory will keep dropping the more i drive it.
Im getting a different launch 2 scanner on thursday to see what it shows up.

[Ck111]

As sort of expected the 650 has become 600 miles remaining, so il need to get something sorted soon before it gets to the point that it wont start.

[PaulC5]

It is probably nothing to do with the usual service countdown but it will not hurt to reset this in case it is nearly 12 months since it was last reset. I do not know how to do it on your car but it will be something like press and hold a button on the dash, turn on the ignition and watch it count down to =0 then let go of the button and you can then start the engine.

[GiveMeABreak]

You can't reset the Adblue counter this way Paul. It will disable vehicle starting at 0 miles and can only be reinitialised with a professional level diagnostic tool. EU rules again.

In this case it's a bit of a joke, as the Adblue is not actually being used it appears, so NOx emissions are not being eliminated as it is.