W245 B 180 cdi P0408 error

[brodev]

Every 2/3 weeks when I start my 2011 B180 cdi car I get an engine warning lamp come on. It gives a p0408 error which resets and the car is fine for another 2/3 weeks. This has happened about 10/15 miles after a motorway run so it is not driving condition induced. Any ideas or do I have little to worry about?

 

[Benzowner]

At the top under sticky is a fault code list, it reads P0408 Exhaust Gas Recirculation Sensor “B” Circuit High