Please add as you feel appropriate:
ABS (Antilock Braking System): Antilock Braking System
ECU (Engine Control Unit): Electronic control unit or Engine control Unit
BCU (Body Control Unit): Body control unit, operates the door locking, alarm system, and so on.
IPK (Instrument pack (IPK from the German)): Instrument pack (IPK from the German)
EWS (Engine immobiliser (EWS from the German, Elektronik WegfahrSicherung)): Engine immobiliser (EWS from the German, Elektronik WegfahrSicherung)
FBH (Fuel burning heater.): Fuel burning heater (only on diesels)
T4 (Testbook version 4.Computer Diagnostic System): Testbook version 4. There are others but the latest and best is the T4. This is used for diagnosing and recoding cars.
VIS (Variable Intake System): Variable Intake System
OP: Original Poster (the person who started the thread)
HTH: Hope that helps
OTOH: On the other hand
SWMBO: She who must be obeyed.