BMW 5 Series Won't Start: AdBlue Tank Issue & Solutions

Hi there! I have some experience with cars, and I dealt with a similar AdBlue issue on my 2015 BMW 3 Series diesel last year. The symptoms were pretty much the same, engine wouldn't start and got those annoying warning lights. Turned out it wasn't just an empty AdBlue tank, the output line from the tank to the dosing unit was faulty. Had to take it to my workshop where they diagnosed and fixed it. Total cost was around 250 Euro, which included parts and labor. Before you jump to conclusions though, could you share more details about the exact error messages you're seeing? Also, when was the last time you topped up your AdBlue? This info would help narrow down if you're facing the same issue I had or if it's something else. If it helps, my mechanic mentioned this is a fairly common issue with BMW diesels from that era.

Hey, thanks for sharing your experience! Facing the same issue right now at 145737 KM. Just had my service done last month and they didn't mention anything about AdBlue levels, which makes me think it might be something more serious. Looking at my dash, I'm getting the 'Engine Start Not Possible' warning along with the DEF system alert. The car was running fine yesterday, and this just happened this morning without any warning signs. Definitely gonna check those output lines you mentioned. Did your car give any warning signs before it completely refused to start? Since we have similar models, really appreciate your detailed insight on this!

Hey again! Yes, my BMW actually did something very similar, worked perfectly fine one day and refused to start the next morning. Looking at what you're describing, it sounds exactly like what I experienced. Those same warnings, 'Engine Start Not Possible' and DEF system alert, were what I got too. The tricky thing is, even though you just had service done, these issues can pop up suddenly. In my case, the line just failed without warning at around 150,000 KM, pretty close to your mileage. The annoying part was that my service a few weeks before hadn't caught any early signs either. One thing I learned from my experience, if you're getting both those specific warnings together, it's usually more than just low AdBlue levels. When it's just low AdBlue, you typically get advance warnings for a few hundred kilometers before it prevents starting. But when the line or dosing unit fails, it happens suddenly, just like what you're experiencing. I'd definitely recommend getting it checked by a workshop that knows these BMW diesel systems well. When they fixed mine, they also installed an updated version of the line that's supposedly more durable. Haven't had any issues since then. Just a heads up, if it is the same problem I had, don't try forcing it to start too many times. I made that mistake and it just drained my battery, adding another problem to deal with!

Thanks so much for all this detailed info, it's really helpful! You've actually made me feel a bit better knowing I'm not alone with this issue. The fact that yours happened at almost the same mileage and with identical symptoms is quite telling. Think I'll stop trying to start it now (was definitely getting tempted to keep trying) and get it towed to the workshop tomorrow morning. Really good to know about that upgraded line they installed on yours too, I'll definitely ask about that when I take it in. Bit frustrating that this wasn't caught during my recent service, but I guess these things just happen sometimes with these engines. I'll probably update this thread once I get it sorted, just in case anyone else runs into the same problem in the future. Really appreciate you taking the time to share your experience. Looks like I've got a workshop visit ahead of me, but at least I know what I might be dealing with!