Lamborghini Gallardo Back Up Light Bulb Size

The Lamborghini Gallardo back up light uses bulb sizes 921 and P21W depending on the specific version of the vehicle. Data for the bulb sizes covers the range from 2004 to 2014.

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

Bulb Size by Year Range

Years	Bulb Size
2009-2014	921
2004-2008	P21W

Bulb Specifications

Description	Bulb Size
ANSI standard (US & Canada). Wedge bulb (T15). 12V, 16W.	921
ECE standard (Europe & worldwide). Single-filament signalling bulb with BA15s bayonet base. 12V, 21W.	P21W

Other Locations

Additional Notes

The Lamborghini Gallardo backup light bulb specification splits across two distinct bulb types depending on model year, with the 921 used in 2009-2014 models and the P21W used in 2004-2008 models.
The 921 is an ANSI-standard bulb, a designation governed by the American National Standards Institute and primarily recognized in the United States and Canada.
The 921 follows the T15 wedge form factor, meaning it uses a wedge-shaped plastic base rather than a metal socket pin or bayonet fitting, and operates at 12V with a 16W output.
The P21W is an ECE-standard bulb, a classification established under the Economic Commission for Europe and recognized across European and international markets.
The P21W uses a BA15s bayonet base, a single-contact fitting where the bulb is inserted and rotated to lock into place, and operates at 12V with a 21W output.
The 921 and P21W are not interchangeable despite sharing the same 12V operating voltage, as they differ in wattage, base type, and governing standards.
The wattage difference between the two bulb types is notable: the P21W draws 21W while the 921 draws 16W, which means substituting one for the other could affect circuit load compatibility.
The base type difference between the T15 wedge (921) and the BA15s bayonet (P21W) means the two bulbs are physically incompatible with each other's sockets without an adapter.