Saturn L200 Back Up Light Bulb Size

The Saturn L200 back up light requires bulb size 921 or P21W depending on the specific version of the vehicle. Data for the bulb size covers the range from 2001 to 2003.

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

Bulb Size by Year Range

Years	Bulb Size
2003	921
2001-2002	P21W

Bulb Specifications

Description	Bulb Size
ANSI standard (US & Canada). Wedge bulb (T15). 12V, 16W.	921
ECE standard (Europe & worldwide). Single-filament signalling bulb with BA15s bayonet base. 12V, 21W.	P21W

Other Locations

Additional Notes

The Saturn L200 back up light specifications reference two distinct bulb standards across its model years: the ANSI-standard 921 and the ECE-standard P21W.
The 921 bulb follows the ANSI standard used in the United States and Canada. It is a T15 wedge-base bulb rated at 12V and 16W.
The P21W bulb follows the ECE standard common in Europe and worldwide markets. It uses a BA15s single-contact bayonet base and is rated at 12V and 21W.
The BA15s bayonet base of the P21W features a single contact point at the base, which corresponds to its single-filament construction intended for signalling functions such as reverse lighting.
The 921 uses a wedge-style base, which is retained by friction rather than a bayonet locking mechanism, making it physically incompatible with the BA15s socket used by the P21W.
The 2003 Saturn L200 specifies the 921 bulb, while the 2001-2002 model years specify the P21W, indicating a base type change between the 2002 and 2003 model years.
The wattage difference between the two bulbs is notable: the P21W draws 21W compared to the 921 at 16W, meaning the two bulbs are not electrically equivalent despite both operating on 12V systems.
Because the 921 and P21W differ in both base type and wattage, they are not interchangeable across the model years listed in these specifications.