DTC P0724: Brake Switch "B" Circuit High [11/2021 - ]: Description

WARNING: This page is about a different car, the 2024 Lexus IS 500, 2023 Lexus IS 500, and 2022 Lexus IS 500. However, it is still accessible from the selected car via links, so may be relevant.

The purpose of this circuit is to prevent the engine from stalling when the brakes are suddenly applied while driving in the lock-up condition.

When the brake pedal is depressed, this switch sends a signal to the TCM. The TCM then cancels the operation of the lock-up clutch while braking is in progress.

DTC No.	Detection Item	DTC Detection Condition	Trouble Area	MIL	Memory
P0724	Brake Switch "B" Circuit High	1. Diagnosis Condition 2. Malfunction Status 3. Malfunction Time 4. Other The engine switch is on (IG) and battery voltage is 8 V or more. The stop light switch remains on. The vehicle is driven in GO (30 km/h (18.63 mph) or more) and STOP (less than 3 km/h (1.86 mph)) pattern 5 times 2-trip detection logic	Stop light switch assembly Short in stop light switch signal circuit TCM	Comes on	DTC stored