Citroen C2 1.1 SX Engine light?

I have purchaced an 54 1.1 C2 SX genuine 7000 miles. On the motor way the engine light bleeped and started flashing - the car lost power but continued to drive. I stopped and strated again and the car drives ok but the light still flashes. Cleared the ECU by disconecting the battery and car drives good but the light is noe on steady all the time. Everything works as it should.

Any ideas?