Porsche Cayman Turn Signal Bulb Size

Porsche Cayman front inner turn signal bulbs use P21W size, while front turn signals require PY21W or 12496 bulbs, and rear turn signals accommodate 12185, 12496, or PY21W bulbs. The replacement chart covers 2006 to 2016 model years with corresponding bulb size specifications for each signal location.

The year-by-year compatibility chart below provides a quick reference to verify the correct bulb size for your vehicle.

Front Inner Turn Signal

Years	Bulb Size
2006-2008	P21W

Front Turn Signal

Years	Bulb Size
2014-2016	PY21W
2011-2012	PY21W
2009-2010	12496
2006-2008	PY21W

Rear Turn Signal

Years	Bulb Size
2009-2012	12185
2007-2008	12496
2006	PY21W

Bulb Specifications

Description	Bulb Size
ECE standard (Europe & worldwide). Single-filament signalling bulb with BA15s bayonet base. 12V, 21W.	P21W
ECE standard (Europe & worldwide). Single-filament amber bulb with BAU15s bayonet base. 12V, 21W.	PY21W
Philips/Osram part number. Halogen bulb, specialty application. 12V.	12496
Philips part number. Halogen bulb, specialty application. 12V.	12185

Other Locations

Additional Notes

The PY21W is the most frequently specified bulb across the Porsche Cayman turn signal positions, appearing in the front turn signal across multiple model years. It follows the ECE standard and produces amber light through a pigmented glass envelope, operating at 12V and 21W with a BAU15s bayonet base.
The BAU15s base used by the PY21W is offset, meaning its two base pins are not symmetrically positioned. This prevents accidental substitution with a standard BA15s bulb, which shares the same 21W rating but uses a straight two-pin base.
The P21W, specified for the Porsche Cayman front inner turn signal across 2006-2008, uses a BA15s bayonet base and operates at 12V and 21W. Unlike the PY21W, it has a clear glass envelope, so the amber signal color is produced by the lens housing rather than the bulb itself.
Both P21W and PY21W are ECE-standardized bulbs, meaning their physical and electrical specifications are governed by international regulation rather than a single manufacturer. This allows multiple brands to produce interchangeable units under those designations.
The 12496 is a Philips and Osram part number for a specialty halogen bulb rated at 12V. It is specified for the Cayman front turn signal in 2009-2010 and the rear turn signal in 2007-2008, indicating a manufacturer-specific fitment rather than a universal ECE type.
The 12185 is a Philips part number for a specialty halogen bulb rated at 12V. It is specified for the Cayman rear turn signal in 2009-2012, and like the 12496, it falls outside the ECE standardized naming system.
Because the 12496 and 12185 are identified by proprietary part numbers rather than ECE designations, substitution with generic bulbs carries a higher risk of fitment or compatibility issues compared to the standardized P21W and PY21W types.
The Porsche Cayman front turn signal position shows a shift between bulb types across its model range. The 2006-2008 and 2011-2016 years use the PY21W, while 2009-2010 use the 12496, indicating that the same position does not share a single bulb specification across all years.
The rear turn signal on the Porsche Cayman uses three distinct bulb specifications depending on the model year: PY21W for 2006, 12496 for 2007-2008, and 12185 for 2009-2012. Selecting a replacement based on position alone, without confirming the model year, would risk an incorrect fitment.
The front inner turn signal position is only listed for the Porsche Cayman in 2006-2008, with the P21W specified across all three of those years.