One problem related to brake light on has been reported for the 2002 Lexus IS. The most recently reported issues are listed below. Please also check out the statistics and reliability analysis of the 2002 Lexus IS based on all problems reported for the 2002 IS.
Car runs great until check engine light comes on followed by vsc and then brake light. When those lights come on it runs rough and brakes make gear noise under driver's side hood area. Brake Is very sluggish and almost non existent when it fails. Let it set, clear fault and runs fine until warm again. Have had all brakes checked and in good condition by mechanic today and problem persists. Appears to be an ecu or other electrical and not mechanical problem. Is extremely dangerous and should be addressed by manufacturer.