A tuner uses a hardware interface (like KESS, KTAG, or PCMTuner) to read the ECU and save the data as a binary file.
Incorrectly modifying a DTC table without understanding the ECU's logic can mask serious mechanical failures, leading to engine damage. Go to product viewer dialog for this item.
A write-up on the "multi DTC editor.exe" utility and its role in automotive tuning. Overview of Multi DTC Editor