DTC P0571/52 Stop Light Switch Circuit: Description

WARNING: This page is about a different car, the 2008 Toyota Camry Solara. However, it is still accessible from the selected car via links, so may be relevant.

The cruise control system cancels cruising when the ECM detects that the brake pedal is depressed while cruise control driving. The stop light switch assembly sends signals to the ECM according to the brake pedal conditions. When the brake pedal is free/terminal ST1- is the positive (+) battery voltage, and terminal STP voltage is below 1 V. While depressing the brake pedal, terminal ST1- is below 1 V, and STP is positive (+) battery voltage. Under braking, the ECM cancels cruise control drive as one of the manual cancel functions.

The ECM outputs this trouble code when voltage of terminals ST1- and STP are both below 1 V for 0.5 second or more at the same moment.

Fail-safe function operates to enable normal driving even if there is a malfunction in the stop light signal circuit.

DTC DESCRIPTION CHART

DTC No.	DTC Detected Condition	Trouble Area
P0571/52	ECM detects a malfunction of the stop light switch circuit under both of the following conditions. Voltage of terminal STP is below 1 V for 0.5 sec. or more. Voltage of terminal ST1- is below 1 V for 0.5 sec. or more.	Stop light switch Stop light switch circuit ECM