BMW M2 Back Up Light Bulb Size

The BMW M2 back up light utilizes 7440 and P21W bulb sizes depending on the specific version of the component. Data for the bulb sizes covers the range from 2016 to 2020.

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
2019-2020	7440
2016-2018	P21W

Bulb Specifications

Description	Bulb Size
ANSI standard (US & Canada). Single-filament wedge bulb (T20). 12V, 21W.	7440
ECE standard (Europe & worldwide). Single-filament signalling bulb with BA15s bayonet base. 12V, 21W.	P21W

Other Locations

Additional Notes

The BMW M2 backup light specifications list two bulb types across the 2016-2020 model years: the 7440 and the P21W.
Both the 7440 and P21W operate at 12 volts and consume 21 watts, making them electrically equivalent in terms of power draw.
Despite their identical electrical ratings, the 7440 and P21W are not physically interchangeable, as they use fundamentally different base designs.
The 7440 follows the ANSI standard used in the United States and Canada. It is a single-filament wedge bulb built to the T20 form factor.
The P21W follows the ECE standard used in Europe and worldwide. It is a single-filament signalling bulb fitted with a BA15s bayonet base.
The BA15s bayonet base of the P21W requires a twist-and-lock installation, whereas the T20 wedge base of the 7440 is held in place by friction alone.
The BMW M2 (2019-2020) uses the 7440 bulb for the backup light position.
The 2016-2018 model years use the P21W, which reflects the ECE-standard fitment common to European-market vehicles.