Porsche Cayenne front inner turn signal bulbs use PY21W size, while front turn signals require 12496 or PY21W bulbs, and rear turn signals use P21W bulbs. The replacement chart covers 2003 to 2010 model years with corresponding bulb size specifications.
The year-by-year compatibility chart below provides a quick reference to verify the correct bulb size for your vehicle.
The PY21W is the most frequently specified bulb across the Porsche Cayenne turn signal positions in these specifications. It is an ECE-standard single-filament amber bulb rated at 12V and 21W, fitted with a BAU15s offset bayonet base.
The BAU15s base of the PY21W uses an offset pin arrangement, which physically prevents it from being seated in sockets designed for the BA15s base. This makes PY21W and P21W bulbs non-interchangeable despite sharing the same wattage and voltage rating.
The P21W is specified for the rear turn signal position across all listed model years, from 2003-2010. It is also an ECE-standard single-filament bulb rated at 12V and 21W, but it uses a BA15s straight bayonet base rather than the offset BAU15s found on the PY21W.
The P21W produces a clear or white light output, unlike the PY21W, which is amber-tinted by its glass envelope. In front turn signal applications, the amber color of the PY21W is integral to meeting signaling regulations rather than being produced by a colored lens alone.
The Porsche Cayenne front turn signal position shows a split specification: 2003-2006 and 2009 use the PY21W, while 2008 and 2010 use the 12496.
The 12496 is a Philips and Osram part number designation for a specialty halogen bulb rated at 12V. Its appearance in the 2008 and 2010 front turn signal positions indicates a different socket or optical assembly was used in those model years compared to years specifying the PY21W.
The front inner turn signal position on the Porsche Cayenne is specified exclusively for 2003-2006, with PY21W across all four of those years. No front inner turn signal entry is present for 2008, 2009, or 2010.
Because the 2009 front turn signal returns to the PY21W after the 2008 model year used the 12496, the two adjacent model years require different bulbs for the same position, making year-specific verification necessary before replacement.