1999 Lexus LS 400 Owners Manual - Page 294

STARTING AND DRIVING 31L003-1 "LOCK" - Engine is off and the steering wheel is locked. The ignition key can be removed only at this position. To turn the key from "ACC" to the "LOCK" position, you must put the transmission selector lever in the "P" position. Once you remove the key, the engine immobiliser system is automatically set. See "Engine immobiliser system" on page 15. When starting the engine, the key may seem stuck at the "LOCK" position. To free it, first be sure the key is pushed all the way in, and then rock the steering wheel slightly while turning the key gently. If, in an emergency, you must turn the engine off while the vehicle is moving, turn the key only to "ACC". 278