Unlike most diesel trucks, VW does not equip their vehicles with a DEF level gauge anywhere in the instrument cluster. This makes it hard to determine how much DEF is in the tank, especially when trying to decide how much DEF to add during a refill. Spilled DEF can be messy and hard to clean up, so checking your level first is always a good idea.
Checking the DEF level requires a scan-tool that can read advanced measuring blocks. The tool of choice on all VWs and Audi is VCDS from Ross Tech. The procedure for checking your DEF level varies by model.
2015 Mk6 Jetta & Beetle
2015 Mk7 Golf & Sportwagen
2012-2014 Passat TDI
2015 Passat TDI
Touareg TDI
Mk7 Golf & Sportwagen
Open up VCDS, select Engine.
Select Advanced Measuring Values
A screen will pop up with a lot of options. The best way to find the fields we need is to type ‘level’ into the search text box at the top of the window.
With ‘level’ in the search the results will be narrowed down. Near the middle of the page will be “Reducing agent fill level”. Clicking the checkbox on that line will make the reading appear in the VCDS window to the left.
In this vehicle the fill level is 80.52%.
2015 Jetta TDI & NMS Passat TDI
Open up VCDS, select Engine
Select Advanced Measuring Values
A screen will pop up with a lot of options. The best way to find the fields we need is to type ‘level’ into the search text box at the top of the window.
With ‘level’ in the search the results will be narrowed down. Near the middle of the page will be “Sensor for reducing agent fill level”. Clicking the checkbox on that line will make the reading appear in the VCDS window to the left.
Important! On the NMS Passat this reading is NOT an actual reading of the fluid level. While this vehicle the fill level shows 77% that does not mean that the tank is 77% full. There are only three possible positions 33%, 77%, and 100%. VeeDubTDI on TDIClub explained it best, “the AdBlue tank only has a 3 position level probe (empty, low, enough).” A 77% reading is, actually, a “low” reading.
Based on observations, it seems that a 100% fill reading can be achieved with 1.5 gallons in the fluid tank. The tank capacity is 4.5 gallons. Therefore, if your tank reading is below 100% it should be safe to add 3 gallons to the tank without overfilling. However, if your tank is reading 100%, it could have anywhere between 4.6 and 1.5 gallons in it, and there is no way to tell how much to add.
