I would like to know how to disconnect my ECU (Bosch EDC16C33 - year 2005) without risk (residual current, short circuit, etc ...).
We're gonna assume I just shut off the engine.
Do I wait before disconnecting the battery?
To disconnect the battery, I start with the "-" (black), right?
And do I wait before unplugging the "+" (red) terminal, or can I do it immediately?

The battery being disconnected, again how long do I wait before disconnecting the ECU?
The goal is that there is no more residual current stored in the capacitors of the ECU when disconnecting it, and also the other ECUs (ABS, dasboard, electric power steering, etc ...).

How do you do it?

MCU and board built to resist temperature and static electricity. By default rule is disable power before disconnecting ecu - like fuse/battery.

its always good to remove battery but even without disconnecting its fine (tested :D :D :D )

- Disconnect battery (first - after +) When reconnect do it inverted
- Wait 10 min