Engine management warning but no issues.
 

W205 C class 3 and a half years old with 28,200 miles

2 months after the warranty run out while using the engine to brake the car down a steep hill the engine diagnostics light came on. I phoned Mercedes me as I was on holiday and they said if the car drives normally and there was no warming message then carry on with the holiday. 4 days later the light went out.

Today with the car 3 and a half year old the warning light has returned but again the car drives normally with no messages.

Do I ignore and hope the light goes out again as I will be selling the car in around 6 months time?

Do I take it to a dealer and hope Mercedes contributes to whatever the issue is?

Do I take it to an independent in the hope of saving on dealer prices if Mercedes doesn’t contribute?

Finally what sort of things would bring the warning light on without a message?