Coding - engine on or off?

[JTM09]

I recall doing a TTFS tune on my old E46 M and the engine had to stay on or hook the car to a battery charger to avoid draining the battery.

Does coding options take as much juice to flash the ECU? Is it better to have the car on or off when coding? Thanks

[Almaretto]

Quick changes can have engine off, but better to have on or connected to external charger to avoid auto-off and corrupting ECU's.

[JTM09]

Thanks man

[Almaretto]

Originally Posted by JTM09

Thanks man