Hyundai Ioniq 5 Brake Bulb Size

Hyundai Ioniq 5 Center High Mount Stop Light utilizes a P21W or PY21W bulb size for this specific component. The replacement chart covers 2023 to 2024 model years with corresponding bulb specifications.

The year-by-year compatibility chart below provides a quick reference to verify the correct bulb size for your vehicle.

Center High Mount Stop Light

Years	Bulb Size
2024	P21W
2023	PY21W

Bulb Specifications

Description	Bulb Size
ECE standard (Europe & worldwide). Single-filament signalling bulb with BA15s bayonet base. 12V, 21W.	P21W
ECE standard (Europe & worldwide). Single-filament amber bulb with BAU15s bayonet base. 12V, 21W.	PY21W

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Additional Notes

The Hyundai Ioniq 5 Center High Mount Stop Light uses two distinct bulb types across its model years: the P21W for 2024 and the PY21W for 2023.
Both the P21W and PY21W operate at 12V with a 21W output and follow the ECE standard, which governs lighting equipment across Europe and numerous other markets worldwide.
Each bulb carries a single filament, meaning neither supports dual-intensity functions such as combined running and brake light operation within the same unit.
The P21W uses a BA15s bayonet base, while the PY21W uses a BAU15s bayonet base. Although these bases appear physically similar, they are not interchangeable due to offset pin positioning on the BAU15s.
The PY21W is an amber-tinted bulb by design, whereas the P21W produces a clear output. Substituting one for the other would alter the color output of the Center High Mount Stop Light.
The base incompatibility between BA15s and BAU15s serves as a mechanical safeguard against incorrect fitment, as the offset pins on the BAU15s prevent it from seating in a BA15s socket.