VW Golf TDI Won't Start: Low AdBlue Tank Alert

Had the same issue on a 2012 VW Passat TDI. The dashboard alert showed the AdBlue system fault and stored an error code related to the SCR catalyst dosing. The root cause was a blocked connection between the AdBlue tank and the dosing unit. The injection system could not deliver the required amount of AdBlue to meet emission standards. This triggered the engine protection mode, preventing starts to avoid damage to the emissions control components. The repair required: Cleaning the AdBlue tank sensor, Replacing the dosing module, Flushing the delivery lines, Refilling with fresh AdBlue, Resetting the system with diagnostic tools This was a serious repair that took about 6 hours at the shop. The car would not run until fixed, as its a vital emissions control component. Without proper AdBlue dosing, the SCR catalyst cannot effectively reduce harmful NOx emissions. The fault is relatively common on these models when they reach higher mileage. Regular AdBlue top-ups and using quality fluid help prevent these issues. Getting it fixed quickly is important to avoid additional damage to the SCR system.

Thanks for sharing that detail on the AdBlue system repair. My Golf had nearly identical symptoms last year with the diesel exhaust system. The dashboard alert came on suddenly and the engine protection kicked in. Actually wondering if we had the same exact issue since the repair steps sound familiar. Did your mechanic also check the tank capacity sensor? Mine was giving false readings which confused the whole injection system. Can you remember roughly what you paid for the full repair? Curious if prices have changed since then. Also, has your AdBlue system worked properly since the fix or have you noticed any other problems?

Your concern about the tank capacity sensor is spot on. The repair on my Passat tackled the exact same issue with the AdBlue system. The mechanic found the connection from the tank to the dosing unit was defective, which was causing incorrect fluid level readings and disrupting the diesel exhaust treatment. The total repair cost came to 250€ which included replacing the faulty components and labor. Since having it fixed, the fuel efficiency and emission standards compliance have been perfect. The injection system is working as intended with no dashboard alerts or other issues for several months now. The repair definitely solved the problem completely. Regular AdBlue levels are maintained without any false readings or system errors. This seems to be a common repair on these VW models, and getting it done properly by a qualified mechanic is crucial for maintaining proper emissions control function.

Thanks everyone for the helpful replies. Just got back from the shop and wanted to share how it went. The service light issue turned out exactly like you described, faulty sensor readings and blocked lines in the injection system. Took it to a diesel specialist who diagnosed the emissions control problem right away. They cleaned out the entire system, replaced the dosing unit, and got everything recalibrated. The tank capacity sensor was also acting up, just as mentioned. Total bill came to 290€ which seems fair compared to what others paid. The whole job took about 5 hours. Really glad I went with a specialist who knew these systems well. The diesel exhaust system is working perfectly now. No more warning lights or starting issues. Going to be more careful about regular AdBlue checks from now on to avoid this happening again. Really appreciate all the advice that helped me understand what I was dealing with before heading to the shop. Having that knowledge made me feel more confident about the repair process.