BMW 440i Gran Coupe front turn signal bulb size is PY24WNA and rear turn signal bulb size is P21W. Replacement chart covers 2017 to 2018 vehicle production 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 440i Gran Coupe uses two distinct bulb types across its front and rear turn signal positions: PY24WNA for the front and P21W for the rear, both for the 2017-2018 model years.
The PY24WNA is an ANSI-standard bulb intended for the US and Canadian markets. It operates at 12V and draws 24W, with a PGU20-4 base.
The PY24WNA is the amber variant of the ECE PY24W. The "NA" designation reflects its North American market specification rather than a separate bulb family.
The front turn signal application of the PY24WNA on the BMW 440i Gran Coupe is conditional, applying only to vehicles equipped with HID headlamps.
The P21W is an ECE-standard single-filament bulb rated at 12V and 21W. It uses a BA15s bayonet base, which is a single-contact base with a 15mm collar.
The P21W is a widely used signalling bulb across European and global automotive applications. Its ECE origin distinguishes it from the ANSI-governed PY24WNA used at the front.
The PGU20-4 base of the PY24WNA is not interchangeable with the BA15s bayonet base of the P21W, making front and rear bulbs physically incompatible with each other's sockets.
The amber coloring of the PY24WNA is built into the bulb envelope itself rather than produced by a colored lens, which is a requirement under ANSI standards for front turn signal applications.