The car is 1.5kmi out of the warranty. CEL is for DEF fill level sensor. Technically the whole active DEF tank should be replaced, because sensor is built-in to it. Dealer wants ~$1300-$1400 for this (parts and labor). I believe it is a part of the same problem I did have in July (look below) I did have similar CEL coming on in July (while the car was under the warranty). I clearly remember, that then SA told me, that sensor is giving the results out of range, but on the papers is shown, that they replaced the DEF injection valve (or something like that), and nothing is said about the sensor. I got couple questions now: 1) Is it possible to force the dealer to replace the tank under the warranty 2) Does anybody know where is the fill level located in the DEF tank and what wires pigtale is coming to it?
The dealer could do something called goodwill assistance on this but it is there decision. Another thing you could do is call BMW customer service and see if they can help. As for the sensor I have seen this before in the diesels and the only right way to fix is to replace the tank it is a sealed system and no way can be repaired without damage.
Is there any wiring diagram or WDS available for this car? The only WDS or TIS I did see online was for the ~2007-2008my cars. As another opportunity I'm considering the bypassing the sensor (just need to know what wires are going to it and where). Because I do refill AdBlue by myself regularly I'm not afraid for situation to happen when I'm running out of DEF (let's say if sensor "thinks" that tank if full all the time). I did flush the DEF tank with ~15 gallons of warm water, but it seems doesn't help. The idea was, that this fluid may crystallize causing the sensor to read incorrect data, so I was trying to "melt" the crystallization.
Pictures of the assemblies are on http://www.realoem.com/bmw/partgrp.do?model=ZW03&mospid=52205&hg=16 Rather than create a new category, they put them in "fuel tank"... why oh why. It appears you're in Illinois? Too bad you aren't in a CA state where you would be covered. Can try that angle, too. But I would argue (politely) with the service manager that this is a known and recurring problem, that the design is crap because it requires replacing the whole tank, and that they should fix it.
I meant I know where the wires are coming out from the tank, but just wanted to find out which of those wires corresponds to the level sensor. I've been talking once during the maintenance with the SA, and they told, that tank replacement cannot be covered with the warranty. So now I'm trying the workaround. Want to by-pass the level sensor with the appropriate resistor. But just need to find out what are the exact wires going to the sensor.
