VW MK4 1.8T 20v Tunes

The MK4 Golf, GTI and Jetta carried the 1.8T 20v in five engine codes, and the calibration is written per code. The early AWD (2000-2001) and the New Beetle's APH run a K03 turbo with a narrowband oxygen sensor. The AWW (2000-2005), the AUM (2001-2005, outside North America) and the 180 hp AWP (2000-2005) run the K03s with a wideband sensor. Stock output is 150 hp on every code but the AWP.

All five take Stage 1 and Stage 2. The wideband codes go on to Stage 3 on a K04 and Stage 4 on a big turbo; the AWD and APH need a wideband conversion first. Program switching is available on the AWW, AUM and AWP. Not sure which code is in the car? Read the engine code guide. For what each stage does and what the car needs before it, read the 1.8T 20v guide.