What is a reprogrammable ECU?
The ECU, or engine control unit, is part of your car's computerized brain and is responsible for monitoring and controlling all aspects of engine operation. For those not interested in upgrading their car for performance, a stock ECU is all it takes. However, if you are planning to build a high performance machine, you will need a reprogrammable engine control unit that can be flashed to change the performance of your engine.
Stock ECU
Your vehicle comes with an unchangeable ECU (with some very minor exceptions). It runs on software that can sometimes be upgraded, but only to the best version of the automaker's software, and then rarely. Sometimes you can "customize" the default settings, but this is also limited. They are pre-installed at the factory for your car's engine as it was when it was built. If you've made modifications to the engine meant to increase power, there's a chance the stock ECU won't cut it. Most ECUs are not programmable/reprogrammable. However, there are aftermarket options that can be reprogrammed.
Reprogrammable aftermarket ECUs
Aftermarket programmable ECUs replace your stock computer with an aftermarket computer. They are designed to allow you to tune almost any engine parameter, from ignition control to intercooler control and more.
Setting up a reprogrammable ECU is usually simple - you connect the ECU to a computer that has the desired software installed. Engine controls and settings are displayed using this software and can be adjusted using the mouse or keyboard. However, it is very important that only a well-trained professional adjust the engine settings. If you're not entirely sure what you're doing, it can be very easy to disable the entire engine.
Do you need a reprogrammable ECU?
Chances are you don't need a reprogrammable ECU unless you're doing major modifications to your car's engine to improve power and performance. In this case, even programmable standard ECUs will not offer unlimited access to the systems and settings necessary to achieve the desired level of performance.
