No I didn't disconnect the battery... also the car refused to start after leaving the lights on for around 5 minutes (with the fogs). I waited for another 5 minutes and it finally started. If I didn't disconnected the battery, may I have damaged the ECU by disconnecting/reconnecting the cluster ?
Also, I tought that checking the codes with the "key-on + 3 seconds + 5 floor gas + 7 seconds + floor for 10 seconds" is supposed to reset codes. I am right ?