[ToolmanJohn]

If it was very low, the dealer has to perform a reset. The manual shows a procedure (you have tried it already) and that reset doesn't work if the tank actually runs low.

It may require a flash of the ECU (the first time it happened to me, they had it for 2 days, flashed the ECU to rid the system of the low AdBlue warning, it has not come back yet).

I have taken to the habit of topping off the AdBlue the end of each month now that I am out of the free maintenance period. Usually 1/2 gallon or so. I am hoping there will never be another message again and smooth sailing.

 

[ToolmanJohn]

Decided to get some more AdBlu and top up the tank until full, took about 16 litres in total. Tried the reset as per manual and threads, no joy. See what the Dealer says tomorrow.

Thanks ToolmanJohn

Unfortunately it looks exactly like the symptoms I had last year when my TDI did the same thing after a dealer service. 2 weeks after a service visit (20K Miles) low AdBlue warning. They could not eliminate the warning without a flash of the ECU. They had to work with VW Germany to fix it. No parts were changed per the service report, just a software flash update.

Then this year , after the 30K service, I checked the AdBlue level after a couple thousand miles.No warning, but it was down by almost 4.5 gallons. I topped it off myself in disgust. I don't have any trust of their service department at all.

 

[ToolmanJohn]

So if I top off the AdBlue before I get a warning the system will "know" it was topped off and I shouldn't get a warning then?

You'll never get a warning because the level will never get low enough to get a low AdBlue warning. I don't think there is an "AdBlue tank is now full" sensor. Why would there need to be one?

Even if you fill half way, I bet it resets because the low level sensor is now happy.

The ONLY downside to topping off monthly, is that it might mean that you always have some "stale" AdBlue in some small proportion to what is added. BUT this is the same as never running down to empty on a fuel tank. Fuel can also go bad over time, so why don't all these cars just fail when owners fill at 1/4 tank or 1/3 tank or 1/2 tank? Doesn't that mean that there will always be some unused "old" fuel mixing with the fresh? You get the idea.....

I had a level sensor problem on my TDI at around the 20K mark. The dealer had in fact filled it during the service, BUT, the AdBlue sensor ended up with dementia, and reports the "XXXX miles remain" warning. One trip back to the dealer, they only reset it , and the following day, "XXX miles remain"..Hmmmm..What???..... Back to the dealer for 3 days, they had to reflash the software with email help from Germany. OOOOOOOHHH K ....

I decided after the last AdBlue issue in July at the 50K mark, (AdBlue P202B Reductant tank heater short...In July?!?!?!), that I will simply allow the tank to go empty to see if everything is OK. Still under extended warranty. Still time for them to get it right (I hope...)