Viano low coolant warning

I understand your frustration. I own a similar Vito, and I experienced comparable symptoms recently. Have you inspected the radiator hoses for any signs of weeping or small leaks? Also, are you certain that the coolant reservoir cap is sealing correctly? A faulty seal can lead to gradual coolant loss. Before assuming the worst, rule out these simple checks.

Thanks for the quick reply! Radiator hoses look okay, but how would I know for sure? And the coolant reservoir cap seems tight, but is there a way to properly test it? Am I missing something obvious?

While a visual inspection of the radiator hoses is a good start, subtle leaks can be difficult to detect. Try applying some pressure to the hoses while the engine is cool to see if that reveals anything. As for the coolant reservoir cap, a pressure test is the most reliable method, which typically requires specialized equipment. Given the stored error and the potential for further complications like engine overheating, I would advise consulting a qualified technician to diagnose the root cause precisely. A repair cost of 95€ seems appropriate for a cable or plug replacement and might be worth the investment to avoid more serious problems.

Appreciate the advice! Took it to the workshop as you suggested. It WAS a faulty connection as the error code suggested. New connector, topped up the coolant, and the check engine light is gone! The bill came to 95€ as predicted. Thanks!