Common Acronyms & Terms


  • ABS: antilock braking system
  • A/C: air conditioning
  • CEL: check engine light
  • DTC: diagnostic trouble code
  • ECU/ECM: electronic control unit/module – usually refers to engine computer, but each of a car’s systems often has its own ECU
  • GPS: global positioning system – generally refers to the car’s satellite navigation system
  • HVAC: heating, ventilation, and air conditioning – also referred to here as climate control
  • LSD: limited-slip differential
  • MY: model year – e.g. “MY05” means model year 2005
  • OBD/OBD2: onboard diagnostics
  • OEM: original equipment manufacturer
  • PCV System: positive crankcase ventilation system – part of modern cars’ emission control systems which recirculates engine gases back into the engine
  • PPI: pre-purchase inspection
  • SAI: secondary air intake
  • SRS: supplemental restraint system – think of it as the “airbag system”
  • TC: traction control
  • TPMS: tire pressure monitoring system
  • TSB: technical service bulletin – issued by manufacturer to mechanics for a widespread issue that isn’t serious enough to be a full recall
  • VIN: vehicle identification number
  • VVT: variable valve timing


  • DSC: Dynamic Stability Control
  • iDrive: BMW’s passenger computer interface
  • M: BMW’s performance division
  • Mechatronic: The “heart” of many automatic transmissions from ZF
  • PDC: Park Distance Control
  • SMG: sequential manual gearbox – a much-derided transmission option offered on some of BMW’s cars in the early 2000’s
  • Valvetronic: BMW’s variable valve lift system
  • VANOS: BMW’s variable valve timing system
  • xDrive: BMW’s all-wheel drive system

Land Rover

  • Alpine Windows: Small upper rear windows primarily featured on the Discovery 1 and Discovery 2
  • Bosch Engines: Refers to 4.0L and 4.6L Rover V8 engines produced from MY99-04
  • GEMS Engines: Refers to 4.0L and 4.6L Rover V8 engines produced from MY95-98
  • Lucas Engines: Refers to 3.5L, 3.9L, and 4.2L Rover V8 engines


  • PDK: Porsche’s dual-clutch automatic transmission, which replaced the TipTronic
  • PSM: Porsche Stability Management – essentially, traction control
  • VarioCam: Porsche’s variable valve timing system