Cars such as 2001 to 2003 LS 430's require Toyota Type IV automatic fluid.

Do you check it cold, hot, running or engine off?

Checked mine off and cold. It was full. However, I needed to add another quart to keep it from slipping as I backed out of my garage and slightly up hill.

What is correct?

 

Looked in my manual for 2001 LS430 and does not tell you how to check it but I have always done hot running. I think it tells you on the dipstick when you pull it out but not sure without looking.

 

Always check when hot, running in P. If you added a quart when it showed full while cold, you are overfilled.

 

If I remember correctly, when I had my radiator replaced years ago at Lexus, I was told to check it after driving to operating temperature, shut the car off for 30 minutes, and then check again while idling. Owning a 2001, I'm aware how blessed I am to have an actual dipstick. It's a royal pain checking 04-06s.