i have been told that the ecu will reset if the battery is left disconnected for any length of time, is this true and if so what do you need to do to restart, if anything. I ahve no red key btw.

I had the battery disconnected from my punto for about 24hrs to charge it, i have a red key however after i connected it back up i didnt give it a second thought and used the blue key - fired up with no problems...........as for resetting the ECU its supposed to so im told.

yeaah it does reset the ECU. No red key is needed

The mk1 at least has a procedure for resetting the ecu.

1- switch the engine on until fan comes on, then goes off
2- when fan comes on again, switch engine off, disconnect neg on battery for 30 secs
3- restart and let it idle for a bit.

the ecu will be reset and will run like poo fora bit and idle funny untill itlearns