Circuit Description
WARNING: This page is about a different car, the 2003 Lexus ES 300. However, it is still accessible from the selected car via links, so may be relevant.
NOTE:
Brake switch may also be referred to as stoplight switch.
Signal of stoplight switch is used to judge whether acceleration system is abnormal or not. Stoplight switch has a duplex system (signals STP and ST1-) to memorize abnormality when signals of depressing and releasing brake pedal are detected simultaneously. For normal condition, see BRAKE SWITCH "A"/"B" NORMAL CONDITION table.
If DTC is set, ignition switch is on, brake pedal is released and STP signal is off when ST1- signal is off. Possible causes are short in stoplight switch signal circuit, faulty stoplight switch, and/or faulty ECM.
BRAKE SWITCH "A"/"B" NORMAL CONDITION
| Signal | Brake Pedal Released | In Transition | Brake Pedal Depressed |
|---|---|---|---|
| STP | Off | On | On |
| ST1- | On | On | Off |