do have to disconnect the battery?
unplug the battery
and pump the brake pedal a few times to get rid of residual power
and if you want let it sit for a little
and thats it
^^^ Sometimes that works, sometimes it doesn't. I've had it not reset like that on me 2 times last year. Since then I've just reset it via software. Resets every time that way.
Try searching for Vishnu ECU reset. There is a section on the fastest way to advance the multiplier for performance gain.
^^^ Not always a good thing to do... especially in a case where the engine is having det issues from a bad tune or otherwise prior to the reset. Besides, if all is well IAM will advance within a few miles anyway. There are other things that take time to learn proper curves in the ECU tables besides the IAM in order to get perfect power and drivability from the tune on the ECU. An advanced IAM is about 25% of the entire equation.