Reset ECU correctly

[Vyse]

In order to perform an ECU reset, say after a battery change, does it matter if it is done with a cold or warm engine? Also, how important is it to let the car idle for 10-15 minutes after reconnecting the battery?

Thanks

[E-bmw]

I personally have no idea but if you narrow it down a bit by letting us know which car, why you need to reset which ECU (modern cars have several) then maybe, just maybe someone may be able to help.

[Heaveho]

Google the specific car, it'll be on the net somewhere. On a lot of the stuff I've owned, just disconnecting the battery for a short period is all that's required, however, one or two I've owned have required different electrical loads such as lights and heaters be applied for a few mins to help reset the base idle speed.

[fatjon]

And others will not reset the base idle speed at all without the diagnostic interface telling them to.
And most don't lose any data or reset anything when disconnected anyway as it is all held in NVRAM.

[E-bmw]

fatjon said:

And most don't lose any data or reset anything when disconnected anyway as it is all held in NVRAM.

^^^^ Wot 'e said.