The Megan as with all new Renaults, have a way of switching off warning lights from inside the car,no tools no fancy machines to plug it into.
Most sales members can turn the warning light off for you very simply.
They will not show you how it's done,as you would switch the warning light off,but not fix the fault.
I have a Renault Capture.
The engine management light went on last month.
As the car was only months old,I switched the engine off,phoned the dealership.
They told me to bring it in,it would only let me drive at a max of the ray miles an hour.
But within two minutes,the sales rep sat in the driver seat,used the buttons on the dashboard and staring wheel.
And turned it off,that easy.
Call you're local Renault dealer.
Stephen, September 2015