I have searched the Owner's Manual and in spite of the service advisor's claim, there is NOT any information on entering a security code that I can find.
Has anybody found this information somewhere? Thanks

 

I was misinformed by the Lexus service advisor. I asked him to find the info in the Owner's Manual (it isn't there). He checked with someone else and found that my car does NOT have a security code to enter
The words "Theft Deterrent Design" printed on the cassette door was a bit misleading...