The BMW 640i Gran Coupe high beam and low beam headlight bulbs both utilize the D1S size. The replacement chart covers 2013 to 2015 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 BMW 640i Gran Coupe uses the D1S bulb for both high beam and low beam headlights across the 2013-2015 model years, with all fitments requiring HID headlamps.
The D1S is a high-intensity discharge (HID) xenon bulb operating at 85 volts and 35 watts, which places it in a different electrical category than conventional halogen bulbs.
A defining feature of the D1S is its integral ignitor, meaning the ignition component is built directly into the bulb unit rather than housed separately in the vehicle's ballast system.
The D1S uses a PK32d-2 base, which is a keyed connector designed specifically for projector-type headlamp housings and is not interchangeable with reflector-type housings.
Because the same D1S bulb serves both the high beam and low beam functions on the 640i Gran Coupe, the projector housing controls beam switching mechanically rather than through separate bulb units.
The D1S is governed by ECE standards, a regulatory framework used in Europe and many markets worldwide, which defines its electrical and photometric performance requirements.
The PK32d-2 base is keyed in a way that prevents substitution with closely related types such as the D2S or D3S, which use different base configurations despite similar operating principles.