C5 AdBlue Tank Error

Sounds like a pain! Is the service light also on, accompanying the dashboard alert? Have you checked the SCR catalyst or the injection system recently? Wondering if those could be related or if it's isolated to the tank itself. How much AdBlue does the tank hold anyway?

SCR catalyst seems fine, but injection system question is interesting. What should I check there specifically?

Yeah, it could be a red herring, but worth a look. Really sounds like that tank output is the problem as you suspected. With the error codes pointing directly to a potential fault in the AdBlue output from tank, you know? For peace of mind and accurate fix, I'd schedule a visit to a workshop. I'd bet on them changing that defective output. The tank capacity should be plenty for it not to run empty often, right?

Confirmed, defective AdBlue output. Replaced it for 250€. Thanks for the input.