DieselTronic piggyback ECUs are aftermarket engine control units designed to enhance the performance of diesel engines. They work in conjunction with the factory ECU, intercepting and modifying sensor signals to optimize fuel delivery, ignition timing, and other parameters. The piggyback design allows for easy installation and removal without permanently altering the vehicle's original ECU. DieselTronic piggyback ECUs typically offer features such as adjustable tuning maps, improved throttle response, increased power and torque output, and in some cases, additional functionalities like launch control or anti-lag systems. They are popular among enthusiasts and performance-oriented diesel vehicle owners looking to extract more power and efficiency from their engines.