IMMO (Megamos)
- VW's first electronic immobilizer family — Megamos Crypto chip with mechanical key + transponder head
- Used across the entire pre-MQB VW lineup
- Golf Mk4/5/6 1996–2011, Jetta Mk4/5 1998–2010, Passat B5/B6 1998–2010, Beetle 1998–2010, GTI Mk4/5 1999–2010, Rabbit (Mk5 Golf NA name) 2006–2009, Cabrio 1999–2002, EOS 2009–2010, CC 2009–2011
- Multiple sub-revisions with progressively stronger encryption over the era
Golf Mk4/5/6Jetta Mk4/5Passat B5/B6Beetle (NB)GTI Mk4/5RabbitCabrioEOS (early)CC (early)