The three main types of VW TDI immobilizer are immo2, immo3, and immo4. VW up to 1999 don't have an immobilizer because immo generation 1 was not equipped on Volkswagen sold in North America. 1999-2000 should have immo2. 2001-2005/6 use immo3. 2005/6-present use Immo4. Around 2010, VW keys changed their design even though they still use immo4. As of this writing, immo5 is only found on the newest Audi. Immo2, 3, 4, and 5 keys are not compatible. In other words, if you have an immo2 car, you can only use an immo2 key because the chip is different.