VW Tiguan Won't Start: Empty AdBlue Tank Alert

Had this exact issue with a VW Passat 2015 diesel. The DEF fluid system showed similar symptoms, causing the engine management to prevent starts. This is a common protection feature when the diesel exhaust treatment system detects issues. The dashboard alert indicated low AdBlue at first, but the actual problem was the dosing unit between the tank and injection system. The dosing module had failed, preventing proper DEF fluid flow to the SCR catalyst. This is a serious issue since it affects the entire emissions control system. The repair required replacing the complete dosing unit and cleaning the DEF fluid lines. The fuel efficiency remained unaffected after the fix, but leaving this problem unattended can lead to catalyst damage. For your Tiguan, its likely showing the same fault pattern. The system will typically give several warnings before completely preventing starts. Get it checked soon, the repair isnt optional since the car will eventually refuse to start to protect the emissions system. Best to have a professional diagnose it properly, as there could be multiple points of failure in the AdBlue delivery system. The issue requires specialized diagnostic equipment to properly identify the exact component causing the malfunction.

Thanks for sharing that experience with the DEF fluid system. Mine got fixed at a dealer but I never got a full breakdown of what exactly they replaced in the injection system. Seems like we had similar issues with the emission standards compliance shutting down the engine. Quick question, would you mind sharing what the total repair cost was in your case? Also wondering if you had any recurring issues with the diesel exhaust system since the fix? Just want to compare notes since these AdBlue system repairs can vary quite a bit in price.

Thanks for asking about the costs. The total repair came to 250€ for fixing the faulty AdBlue output connection between the tank and dosing unit. Since getting that fixed at the shop, the service light hasnt come back on and the SCR catalyst system works perfectly. The dashboard alert for DEF fluid levels now shows normal readings and the car starts reliably every time. The emission control systems been working without any issues for several months now. The repair proved to be a permanent fix, no recurring problems with the diesel exhaust treatment or AdBlue injection. The tank capacity sensors also work correctly now, giving accurate AdBlue level readings. This was actually part of the original problem since the faulty connection made the system think the tank was empty even when it wasnt. A properly working DEF system is crucial, when the dosing unit gets the right fluid flow, the whole emissions setup performs as designed. The repair cost was worth it to avoid potential damage to more expensive components.

After dealing with my Tiguan issues, I finally got it sorted at the dealer. The total repair bill came to 380€, quite a bit more than what you paid. They had to replace both the dosing module and clean out the entire DEF fluid system since it had crystallized in several spots. The emission control system works perfectly now, and the SCR catalyst is functioning as it should. The fuel efficiency actually improved slightly after the fix, which was an unexpected bonus. My dashboard shows accurate AdBlue levels now, and the engine starts right up every time. The mechanics explained that the crystallized AdBlue had clogged up the injection system pretty badly. Would have been cheaper to fix if I had caught it earlier, but at least the diesel exhaust system is working properly now. No recurring issues in the past three months since the repair. Turns out the tank capacity sensor was also affected by the crystallization, which explained the confusing readings I was getting before. Lesson learned about keeping up with the AdBlue maintenance schedule.