BMW X1 front turn signal uses PY21W bulb size while rear turn signal requires P21W bulb size for replacement. The chart contains bulb size specifications covering 2012 to 2022 production years.
The year-by-year compatibility chart below provides a quick reference to verify the correct bulb size for your vehicle.
The PY21W is an ECE-standard single-filament amber bulb rated at 12V and 21W, fitted with a BAU15s offset bayonet base. The offset pin placement of the BAU15s base physically prevents installation of non-amber bulbs, enforcing correct amber output for turn signal applications.
The P21W is also an ECE-standard single-filament bulb rated at 12V and 21W, but it uses a BA15s straight bayonet base rather than the offset BAU15s found on the PY21W. Despite sharing the same wattage and voltage rating, the two bulb types are not interchangeable due to their differing base configurations.
The 12496 is a part number used by Philips and Osram for a 12V halogen bulb designated for specialty applications. It serves as the front turn signal bulb on the BMW X1 for the 2014-2016 and 2019 and 2021 model years.
The rear turn signal position on the BMW X1 uses the P21W across all listed model years from 2012-2022, with no variation across that span.
The front turn signal position alternates between PY21W and 12496 across different model years, meaning the correct bulb type must be confirmed against the specific model year before replacement.
For the 2020 BMW X1, the PY21W front turn signal specification carries an explicit restriction: it does not apply to vehicles equipped with Adaptive LED headlights or LED headlights. This is the only model year in the specifications carrying a headlight-package-based fitment condition.