DTC P0030 Lexus

Description

The SJB monitors the headlight switch position by sending voltage reference signals on multiple circuits to the headlight switch. There is one circuit for each headlight switch position. At any given time, one of the signal circuits is routed to ground. If the SJB does not detect any of the inputs to the headlight switch are active (routed to ground) for 5 seconds, the SJB turns on the exterior lights and keeps them on for 10 minutes after the ignition switch is turned off (or 10 minutes from the time the SJB does not detect any headlight switch input if the ignition switch was already off). Additionally, if the SJB detects multiple circuits short to ground, the SJB implements a planned strategy depending on the multiple inputs received. Based on the multiple inputs received, the autolamps, the headlamps and or the parking lamps are turned on.