The recall affects all Cayenne Turbo models from the 2012 model year and all Panamera Turbo and Panamera Turbo S models from the 2011 and 2012 model years.
There are some 270 models affected by the latest recall in the U.S.
According to Porsche, the turbine wheels on the affected models could fracture due to a casting defect. Should this occur, performance will be decreased but more importantly the turbine shaft may fracture.
If the whole shaft were to fracture, cooling oil may be drawn into the exhaust system, resulting in smoke and the possibility of fire.
Porsche recommends owners affected by the recall take their vehicles to their nearest Porsche dealer which will replace the defective turbine wheels free of charge. For further information you can contact the National Highway Traffic Safety Administration at 1-888-327-4236 (reference recall campaign number 12V329000) or Volvo at 1-800-767-7243.