Audi TTS Quattro front turn signal bulbs use sizes 12174NA, 12174SV, or 12496, while rear turn signal bulbs use size 921 according to the replacement bulb chart. The data covers 2009 to 2023 model years.
The year-by-year compatibility chart below provides a quick reference to verify the correct bulb size for your vehicle.
The 12496 is the most frequently specified front turn signal bulb across the Audi TTS Quattro range, appearing in model years 2009-2015 under HID headlamp configurations and as the sole front turn signal option for 2013-2015. It is a 12V halogen bulb produced under Philips and Osram part numbers for specialty automotive applications.
The H21W is an ECE-standard single-filament signalling bulb rated at 12V and 21W, fitted with a BAY9s bayonet base. On the TTS Quattro, it is specified exclusively for the front turn signal position in 2009-2012 model years equipped with halogen capsule headlamps.
For 2009-2012, the front turn signal bulb type on the Audi TTS Quattro is determined by the headlamp system installed. Vehicles with halogen capsule headlamps use the H21W, while those with HID headlamps use the 12496. These two bulbs are not interchangeable due to differing base types and wattage ratings.
The 921 is an ANSI-standard wedge bulb of the T15 form factor, rated at 12V and 16W. It serves as the rear turn signal bulb across all specified model years of the TTS Quattro from 2009-2015.
The 2021 front turn signal specification calls for the 12174SV, a Philips SilverVision halogen bulb with an enhanced coating, operating at 12V. The 2023 specification uses the 12174NA, a natural amber glass variant sharing the same 12V rating. Both carry OEM-referenced part numbers but represent distinct optical outputs.
The 12174NA and 12174SV share the same base part number series, indicating physical interchangeability in terms of fitment, though their optical coatings differ. The 12174NA produces a natural amber output through tinted glass, while the 12174SV achieves its appearance through a surface coating on clear glass.
The rear turn signal position carries no headlamp-conditional variants across any of the specified model years. A single bulb type, the 921, is listed without qualification for all rear turn signal applications from 2009-2015.
No rear turn signal specification is listed for the 2021 and 2023 model years in the provided data, and no front turn signal specification is listed for years prior to 2009 or between 2016 and 2020.