I'm not quite sure if this is the right forum so I apologize in advance if it needs to be moved. I recently purchased a 2003 MkIV 1.8T Jetta and have started to mess with it some. I was wanting to remove the SAI, EVAP, and Cats which brought me here to figure out how to tune out the codes without paying someone a ton of cash. After starting down the rabbit hole I've seem to hit a weird snag. I downloaded my .bin file with Nefmoto and when I ran the ecu numbers it seems to come back to a 2005 Golf? I've used VCDS and the Vin's all match (ecu, car, and cluster) and don't show a previous VIN. Can this be the original ECU? I bought the car from a mechanic and the more I poke around the more shady things I seem to find (he had told me he put a 225hp audi tt compressor wheel in the stock turbo when he replaced the seals, which I later found out is impossible without machining the housing). I am eager to learn but there seems to be almost no info on this ECU, in addition to it looking like it comes from a 150hp vehicle?? I've attached the ECU read I did this afternoon. Thanks for any and all insight.

is it a 5 or 6 speed? I have a 2004 GLI 1.8t 6-speed 180hp and it is a 06A906032RN ecu. the 2004 GTI has an 06A906032LP ecu...which is the 5-speed AWP 180hp file. I can look around to see what a 2003 is... If there was ever an issue with the ecu/cluster/immobilizer, it is possible someone grabbed the whole kit and caboodle out of a Golf, which would have the 150hp file, and had the vin changed via a flash.

right. and they have quite a number of different heads too...AWW, AWD, AWP ....etc. The 04 GTI and the 04 GLI I had/have both had the AWP head and the 180hp tune...although my gti ecu was 032LP (5-speed) and my GLI ECU is 032RN (6-speed).