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 when brakes have been applied. STP signal voltage is same as voltage supplied to stop lights. STP signal is used mainly to control fuel cutoff engine speed (fuel cutoff engine speed is reduced slightly when vehicle is braking). DTC is set when stop light switch does not turn off even when vehicle is driven (1 trip detection logic). Possible causes are:

Short in stoplight switch signal circuit.
Faulty stoplight switch.
Faulty ECM.