Flashing an ECU is tuning or reprogramming the engine of your vehicle to take what the manufacturer or a previous owner sold you and (ideally) enhance its performance.... A motorcycle's ECU, short for the engine control unit, will sometimes be referred to as an ECM, or engine control module.
Ultimately, ECU Flash Tuning can be a very dangerous and costly addition to your vehicle. If you're wanting more power, the safe choice is a module, installed by a trusted diesel engineer. Unlike ECU Flash Tunes, which re-program your vehicle's on-board computer, a module is a simple plug and play system.
A performance chip does not cause damage to your engine or transmission as it increases the horsepower and torque output. This power is generated mainly by harmlessly adjusting your air/fuel ratio and ignition timing to optimal settings. In fact, a performance chip can even protect your engine from damage.
Most reflashing methods require the use of the four pins in the DLC that are open to the manufacturer. Some reflash sessions can last more than 45 minutes. If the battery voltage drops below a set voltage, the reflashing process will stop and possibly damage the module.