Scion iQ Back Up Light Bulb Size

The Scion iQ back up light uses a 921 bulb size for the lighting component located at the rear of the vehicle. Data for the specific bulb covers the range from 2012 to 2015.

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

Back Up Light

Years	US Type	EU Type	Shop
2012-2015	921	W16W	Check Price

Outer Back Up Light

If US Type and EU Type show the same value, a direct cross-reference for this bulb is not available or the data is insufficient.

Years	US Type	EU Type	Shop
2015	3057 (To 06/2015)	3057	Check Price
2014	3057	3057	Check Price
2013	921 (From 09/2012)	W16W	Check Price
2012	921	W16W	Check Price

Bulb Specifications

Description	Type	Shop
ANSI standard (US & Canada). Wedge bulb (T15). 12V, 16W.	921	Check Price
ANSI standard (US & Canada). Dual-filament wedge bulb (T25). 12V, 27W/7W.	3057	Check Price

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Additional Notes

The 921 bulb is an ANSI-standard wedge type in the T15 form factor, rated at 12 volts and 16 watts, and is recognized across both the United States and Canada.
The 3057 bulb is also an ANSI-standard wedge type but uses a larger T25 form factor with dual filaments, rated at 12 volts with a 27-watt primary filament and a 7-watt secondary filament.
The Scion iQ uses the 921 bulb for the back up light across the full 2012-2015 model range.
The outer back up light on the 2012 and 2013 iQ (from September 2012 onward) also takes the 921 bulb, making it interchangeable with the standard back up light position for those years.
The outer back up light for the 2014 model year and the 2015 model year through June 2015 requires the 3057 bulb, which is a different type from the 921 used in the main back up light position.
Because the 921 and 3057 are both wedge-base bulbs but differ in filament count, wattage, and form factor, they are not interchangeable with each other despite sharing a general wedge-style base design.
The 2013 outer back up light position reflects a mid-year specification, with the 921 bulb applying only to vehicles produced from September 2012 onward, indicating a production change within that model year.
Similarly, the 2015 outer back up light specifies the 3057 only through June 2015, indicating another mid-year production cutoff within that final model year.