I believe it is like the check engine light for the A340 transmission. An error code is stored and tells you there is an issue on the tranny. You need to pull the code so you have an idea what is wrong.
1996 Toyota Supra MKIV 3.4 Stroker 6 speed Targa / ProEFI 128
1994 Toyota Supra MKIV Built 3.0 6 speed HardTop / Haltech PS2000
1992 Lexus SC400 2jzgte Built 3.0 ATF Auto / ProEFI 128
1997 Lexus SC300 2jzgte 3.4 Stroker 6 speed / AEM v2 - Under the Knife (1 of 120 5speed - Last Year of SC300 with Manual Transmission)
1993 Lexus SC300 2jzgte Built 3.0 4l80e Auto / ProEFI 128 - Under the Knife