DTC P0571: Brake Switch "A" Circuit [08/2013 - ]: Description
WARNING: This page is about a different car, the 2014 Lexus ES 300h. However, it is still accessible from the selected car via links, so may be relevant.
When the brake pedal is depressed, the stop light switch assembly sends a signal to the power management control ECU. When the power management control ECU receives this signal, it cancels control of vehicle speed by the cruise control system. The fail-safe function operates to enable normal driving even if there is a malfunction in the stop light signal circuit. The cancellation condition occurs when voltage is applied to terminal STP. When the brake is applied, voltage is normally applied to terminal STP of the power management control ECU through the STOP fuse and the stop light switch assembly, and the power management control ECU turns the cruise control system off.
| DTC No. | DTC Detection Condition | Trouble Area |
|---|---|---|
| P0571 | Voltage of STP signal and that of ST1- terminal of power management control ECU are less than 1 V for 0.5 seconds or more |
|