The Toyota Celica back up light utilizes 921, 1156, and P21W bulb sizes depending on the specific production period for the vehicle. Available data covers a range from 1973 through 2002.
The year-by-year compatibility chart below provides a quick reference to verify the correct bulb size for your vehicle.
The Toyota Celica back up light specifications reference three distinct bulb types: the 921, the 1156, and the 3057, all of which conform to ANSI standards recognized in the United States and Canada.
The 1156 is a single-filament bulb with a BA15s bayonet base, rated at 12V and 21W. It is the most widely specified bulb across the Toyota Celica back up light data, covering model years 1973-1999 for the standard back up light position and 1995-1999 for the outer back up light position.
The 921 is a T15 wedge-base bulb rated at 12V and 16W. It draws less wattage than the 1156 and uses a wedge-style base rather than a bayonet mount, making the two types physically incompatible with each other despite serving the same lighting function.
The 3057 is a dual-filament T25 wedge bulb rated at 12V with a high filament of 27W and a low filament of 7W. Its dual-filament construction distinguishes it from both the 921 and the 1156, which are each single-filament designs.
The Toyota Celica (2002) outer back up light position specifies the 3057, while the standard back up light position for the same year specifies the 921. These two positions on the 2002 model therefore require different bulb types.
The 1156 uses a BA15s bayonet base, which requires a twist-and-lock installation method. The 921 and 3057 both use wedge bases, which are retained by socket pressure rather than a bayonet locking mechanism, and the two wedge types are not interchangeable due to differing body sizes.
For the outer back up light, the specification shifts from the 1156 to the 921 between the 1999 and 2000 model years, and then to the 3057 for the 2002 model year, indicating that the same socket position across these years accepted different base types.