How do you replace ECU on 2001 Miata?

To replace the ECU on a 2001 Miata, first disconnect the negative battery terminal to ensure safety. Locate the ECU, which is typically found behind the passenger side kick panel; remove any screws or clips securing it. Disconnect the wiring harness and any attached connectors, then remove the old ECU and replace it with the new one. Finally, reconnect the wiring, secure the ECU in place, and reconnect the battery before testing the vehicle.