There is no one specific programming language required to remap a car's ECU. The process of remapping an ECU involves modifying the software that controls the engine's operation, and different ECUs may use different programming languages or file formats. In general, remapping an ECU requires specialized software and technical knowledge of engine tuning and car electronics. Some popular car tuning software packages include Wolf V550 PC Software Serial Version A, ProECU, and OBDstation. It is important to note that remapping an ECU can affect a car's performance, fuel efficiency, and emissions, and should only be performed by experienced technicians or enthusiast with proper knowledge and tools.