Mercedes Viano AdBlue Problem

I had a similar issue with my Vito and the error message was triggered because the system thought the tank was empty. The problem was not the level sensor itself, but rather the pump that sends AdBlue to the injection system. Have you checked the pump's functionality? A faulty pump can prevent the AdBlue from being injected, causing the engine to fail to start and triggering the warning lights.

Interesting. So, if I understand you correctly, your level sensor was fine, but the pump wasn't pushing the AdBlue through? Was it a complete failure, or was it just delivering insufficient pressure? I'm trying to diagnose this without throwing parts at it, so any further detail would be great before I start checking the pump.

The pump had failed completely. Diagnostics pointed directly to it, so I replaced it. Given your symptoms and the error codes you're seeing, I'd strongly advise having the pump properly tested. While a blockage is possible, a pump failure is quite common. The cost was around 250€ with labor included. A workshop can confirm if it is the pump or another related component in the injection system.

Cheers for the advice. I appreciate you sharing your experience. Took it to a local specialist, and you were spot on – the AdBlue pump was kaput. Replaced it, and all is now well. Back on the road and the service light has gone off. Thanks again.