BMW 430i front turn signal uses PY24WNA bulb size and rear turn signal uses P21W bulb size. Replacement chart covers 2017 to 2018 model years with bulb specifications.
The year-by-year compatibility chart below provides a quick reference to verify the correct bulb size for your vehicle.
The BMW 430i uses two distinct bulb types across its front and rear turn signal positions for the 2017-2018 model years: PY24WNA at the front and P21W at the rear.
The PY24WNA is an ANSI-standard bulb used in the United States and Canada. It is the amber variant of the ECE-standard PY24W and operates at 12 volts with a 24-watt output.
The PY24WNA uses a PGU20-4 base, which is a wedge-type locating base designed to ensure correct angular positioning of the amber bulb within the housing.
The front turn signal application of the PY24WNA on the BMW 430i is conditional, applying specifically to vehicles equipped with HID headlamps.
The P21W is an ECE-standard single-filament bulb rated at 12 volts and 21 watts. It is used globally across European and international markets for signalling applications.
The P21W uses a BA15s bayonet base, a single-contact bayonet fitting that is one of the most widely standardized bases in automotive signalling bulbs.
The rear turn signal position on the 430i uses the P21W for both the 2017 and 2018 model years without any conditional trim or equipment qualifiers.
The PY24WNA and P21W are not interchangeable. They differ in base type, wattage, color designation, and the regulatory standards under which they are specified.