The BMW M4 high beam and low beam headlight bulbs both utilize the D1S size. The replacement chart covers vehicle production spanning 2015 to 2018 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 D1S bulb type appears across all listed model years of the BMW M4 (2015-2018), serving both the high beam and low beam headlight positions when the vehicle is equipped with HID headlamps.
D1S is a High-Intensity Discharge (HID) xenon bulb operating at 85 volts and 35 watts, which distinguishes it from conventional halogen bulbs that typically operate at 12 volts.
The D1S bulb uses a PK32d-2 base with an integral ignitor built directly into the bulb body, meaning the ignitor and bulb are replaced as a single unit rather than separately.
D1S bulbs are designed specifically for projector-type headlight housings, and substituting them into reflector-type housings would produce incorrect light distribution.
The D1S standard falls under ECE regulation, which governs bulb specifications across Europe and many international markets outside North America.
Because the D1S incorporates an integral ignitor, it is not interchangeable with the D1R bulb type, which shares the same wattage and voltage but carries a different base designation and is intended for reflector housings.