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.

This signal is used to detect that brakes have been applied. STP signal voltage is same as supplied to stoplights. STP signal is used mainly to control fuel cut-off engine speed (fuel cut-off engine speed is reduced slightly when vehicle is braking). DTC is set when stoplight switch does not turn off even when vehicle is driven (2 trip detection logic). Possible causes are:

Short in stop light switch signal circuit.
Faulty stop light switch.
Faulty ECM.