04_is300_sd

I recently had this exact same thing happen on my 2004 is300. the engine light came on then about 5secs later the "trac off" light began blinking slowly. i read on another lexus forum that it had to do with the evaporative sensor in the fuel system and could be fixed by ensuring that your gas cap is screwed on all the way (until it clicks) i did this to mine and no change at first, i drove it around, did some hard braking, still no change. i drove it back home and decided to pop the negative terminal off for about 30secs and put it back on. when i did i put the key in and turned it, all the warning lights came on at first like normal then one by one went off, including the check engine, i put it in gear and went back then forward. i'm not sure if this is a permanent fix but try it on yours and it may work. good luck