Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
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HOMESERVICE MANUALSTOYOTA2006SIENNA FWD V6-3.3L (3MZ-FE)REPAIR AND DIAGNOSISA L L DIAGNOSTIC TROUBLE CODES ( DTC )TESTING AND INSPECTIONP CODE CHARTSP0571CRUISE CONTROL SYSTEM
2006 Toyota Sienna FWD V6-3.3L (3MZ-FE)
Cruise Control System
2006 Toyota Sienna FWD V6-3.3L (3MZ-FE)SECTION Cruise Control System
DTC P0571 Brake Switch "A" Circuit
DESCRIPTION

When the brake pedal is depressed, the stop light switch assembly sends a signal to the ECM. When the ECM receives the signal, it cancels the cruise control. A fail-safe function is provided so that it functions normally, even if there is a malfunction in the stop light signal circuit.
The cancel condition occurs when battery positive voltage is supplied to terminal STP.
When the brake is on, battery positive voltage is normally applied through the STOP fuse and the stop light switch assembly to terminal STP of the ECM, and the ECM turns the cruise control OFF.
If the harness connected to terminal STP has an open circuit, terminal STP will have battery positive voltage and the cruise control will be turned OFF.


INSPECTION PROCEDURE
DESCRIPTION
DTC Detection Condition:
When the brake pedal is depressed, the stop light switch assembly sends a signal to the ECM. When the ECM receives the signal, it cancels the cruise control. A fail-safe function is provided so that it functions normally, even if there is a malfunction in the stop light signal circuit.
The cancel condition occurs when battery positive voltage is supplied to terminal STP.
When the brake is on, battery positive voltage is normally applied through the STOP fuse and the stop light switch assembly to terminal STP of the ECM, and the ECM turns the cruise control OFF.
If the harness connected to terminal STP has an open circuit, terminal STP will have battery positive voltage and the cruise control will be turned OFF.
Wiring Diagram:
Step 1-3:
INSPECTION PROCEDURE
RENDER: 1.0x
NO RELATED
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- β’ You smell fuel, burning insulation, or see smoke.
- β’ Brakes feel soft, pull hard to one side, or make grinding noises.
- β’ The engine overheats, stalls repeatedly, or misfires under load.
- β’ You are missing required tools, torque specs, or safe lifting equipment.
- β’ You are not confident in the next step or safety outcome.