How do you check transmission fluid in 2003 L series sedan?

The 2003 Lexus LS430 (the L-series sedan you're likely referring to) doesn't have a traditional dipstick for checking transmission fluid. Instead, the transmission fluid level is checked by a technician using specialized equipment that measures the fluid level and temperature while the engine is running.

You cannot reliably check the transmission fluid level yourself. Attempting to do so could lead to inaccurate readings and potentially damage the transmission.

If you suspect a problem with your transmission fluid (e.g., slipping, rough shifting, unusual noises), you should take your Lexus LS430 to a qualified mechanic or Lexus dealership. They have the proper tools and expertise to diagnose and address any transmission issues, including checking the fluid level and condition. Simply stating that you need a transmission fluid check will get the message across.