BMW ActiveHybrid 3 Back Up Light Bulb Size

BMW ActiveHybrid 3 back up light bulb uses a P21W size. The replacement chart covers vehicle production years from 2013 to 2015 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.

Bulb Size by Year Range

Years	Bulb Size
2013-2015	P21W

Bulb Specifications

Description	Bulb Size
ECE standard (Europe & worldwide). Single-filament signalling bulb with BA15s bayonet base. 12V, 21W.	P21W

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Additional Notes

The P21W is the sole bulb type listed for the BMW ActiveHybrid 3 backup light across the 2013-2015 model years.
The P21W is an ECE-standard single-filament signalling bulb rated at 12 volts and 21 watts.
It uses a BA15s bayonet base, which is a single-contact bayonet fitting with a 15mm collar.
The BA15s base is not interchangeable with the BA15d base, which carries two contact points rather than one. Using a dual-contact bulb in a single-contact socket results in an improper fit.
The ECE designation indicates the P21W conforms to European and international lighting regulations, as opposed to SAE-standard bulbs used in North American markets.
At 21 watts, the P21W draws more power than lower-wattage signal bulbs such as the 5W or 10W variants, which affects compatibility when substituting bulbs in the same physical base family.