Megane engine control malfunction

I had the same issue on my Megane. Check engine light, and the engine wouldn't even crank. Have you checked the battery cable connections for corrosion or looseness?

Corrosion could be the culprit. Did cleaning the cable connections fix it for you?

Cleaning helped temporarily, but the issue came back. I ended up taking it to a workshop. They confirmed bad connections, but there was also a slight surge that might have affected the ECU. I'd suggest getting it checked by a professional.

Thanks. It was indeed the battery cable connections! Cost me 155€ to get sorted.