konstantinmaier5

AdBlue tank issue on Mercedes S Klasse diesel

My 2020 Mercedes S Klasse diesel is showing an AdBlue tank empty error, even though I'm pretty sure it's not. The service light is on, and the car won't start now. Error memory also confirms it. Has anyone experienced this before? Could it be something to do with the AdBlue output from the tank?

4 comment(s)

Sounds familiar! I have the same model. I had a similar issue pop up not too long ago. Car threw a fit about DEF fluid levels, kept getting dashboard alerts, and eventually refused to start. Did you check for any visible leaks around the AdBlue tank or dosing unit? Just wondering, because I suspect it has to do with the car's emission standards.

Thanks for the quick reply! I haven't noticed any leaks, but I also haven't specifically looked for them. Where exactly should I be checking around the tank and dosing unit? And what was the cause of your issue? Was it expensive to fix?

Right, no worries. I didn't see any leaks either, which made it even more confusing. My issue turned out to be a faulty AdBlue pump, which wasn't pushing the DEF fluid properly. In the end, I had to take it to a workshop. They sorted it out for around 250€. It's tricky to diagnose yourself without the right tools, isn't it? Best to get it checked to prevent further issues with fuel efficiency.

Appreciate the insight! I'll take your advice and get it to a workshop. Sounds like it could be a similar issue with the pump. Thanks again for the help!

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