Audi A5 AdBlue Refill: DIY Fix vs. Workshop Guide

The AdBlue injection system failure you describe matches what happened with my 2016 Audi A6 3.0 TDI. The service light appeared first, followed by the emissions control warning that prevented startup. Initial AdBlue refill did not resolve the issue. The problem was traced to a faulty dosing unit connection where the AdBlue transfers from tank to engine. This is a known weak point that can develop issues around 130000-150000km. The repair required: Complete system diagnosis, Replacement of the dosing module, Cleaning of crystallized AdBlue deposits, Reset of the engine management system This is not a DIY fix as it requires specialized diagnostic equipment to properly reset the emissions control parameters. Simply refilling AdBlue will not solve the underlying technical issue. The repair took 2 full days at an authorized workshop. This was a serious issue that needed immediate attention, continuing to drive risks permanent damage to the SCR catalyst and potential engine shutdown. If your dashboard alert is showing the final warning stage, the car will not restart after shutdown until properly repaired by a qualified technician with the right diagnostic tools.

Thanks for explaining your A6 situation, it sounds very similar to what I am dealing with now. My A5 is also showing that final warning stage and wont start. Getting worried about potential SCR catalyst damage too. Going to bite the bullet and book it into a workshop tomorrow. Do you happen to remember the total repair cost for your dosing unit fix? Also wondering if youve had any issues since getting it repaired? Just want to know what I might be in for when I take it in.

Actually took my A6 to the workshop last week for this exact AdBlue tank issue. The fault was exactly what I suspected, the connection between the tank and dosing unit was defective, preventing proper flow into the diesel exhaust system. Total cost came to 250 Euro for the repair, which included cleaning the crystallized deposits and resetting the emissions control parameters. The workshop confirmed this is quite common on these models at higher mileage. Since the repair, the injection system has been working perfectly, no warning lights or starting issues. The tank capacity sensor is now reading correctly and the emissions control system is functioning as it should. Going to a qualified workshop was definitely the right choice. They had the proper diagnostic equipment to properly reset everything, which is essential for meeting current emission standards. For peace of mind, have them check your SCR catalyst while they are at it. Mine was fortunately undamaged because I stopped driving as soon as the warnings appeared.

I finally got the car back from the workshop today. After your advice, I took it to a certified shop instead of trying a DIY fix, and Im really glad I did. The diagnosis showed exactly what you described, a failed dosing module and crystallized deposits blocking the injection system. The mechanic confirmed continuing to drive would have damaged the SCR catalyst. Total repair cost was 280 Euro, slightly more than yours but still reasonable considering the complexity. They did a full emissions control system check, replaced the dosing unit, and cleaned out all the old AdBlue residue. Car starts perfectly now and all dashboard alerts are cleared. Fuel efficiency seems better too, probably because the system is working properly again. The mechanic suggested checking AdBlue levels monthly to catch any future issues early. Really appreciate the guidance, saved me from making an expensive mistake trying to fix it myself. Good to know these issues are common and fixable when handled correctly.