Toyota Sienna Service Manual: Brake Switch "A" Circuit
DTC P0571 Brake Switch "A" Circuit
DESCRIPTION
When the brake pedal is depressed, the stop light switch sends a signal to the ECM. When the ECM receives this signal, it cancels the cruise control. 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 ECM through the STOP SW fuse and the stop light switch, and the ECM turns the cruise control off.
|
DTC No. |
DTC Detection Condition |
Trouble Area |
|
P0571 |
Voltage of STP terminal and that of ST1- terminal of ECM are less than 1 V for 0.5 sec. or more |
|
WIRING DIAGRAM
INSPECTION PROCEDURE
1 READ VALUE OF INTELLIGENT TESTER
- Connect the intelligent tester to the DLC3.
- Turn the ignition switch to the ON position, and turn the intelligent tester main switch on.
- Check the DATA LIST for proper functioning of the stop light switch.
ECM (Cruise control):
OK: When the brake pedal is operated, the display changes as shown above.
REPLACE ECM
2 CHECK HARNESS AND CONNECTOR (STOP LIGHT SWITCH - BATTERY)
- Disconnect the S12 stop light switch connector.
- Measure the voltage according to the value(s) in the table below.
Standard voltage
3 INSPECT STOP LIGHT SWITCH
- Remove the stop light switch.
- Measure the resistance according to the value(s) in the table below.
Standard resistance
4 CHECK ECM
- Reconnect the S12 stop light switch connector.
- Disconnect the E4 connector from the ECM.
- Turn the ignition switch to the ON position.
- Measure the voltage according to the value(s) in the table below.
Standard voltage
REPLACE ECM
Vehicle Speed Sensor Malfunction
DTC P0500 Vehicle Speed Sensor Malfunction
DTC P0503 Vehicle Speed Sensor "A" Intermittent / Erratic /
High
DESCRIPTION
The cruise control system uses the same vehicle speed signal that ...
Stop Light Switch Circuit Malfunction
DTC P0571 Stop Light Switch Circuit Malfunction
DESCRIPTION
The ECM receives the brake demand signal from the distance control ECU and
transmits it to the skid
control ECU (brake actuator assembl ...
Other materials:
On-vehicle inspection
1. INSPECT STEERING PAD (VEHICLE NOT INVOLVED IN COLLISION)
Perform a diagnostic system check.
With the steering pad installed on the vehicle,
perform a visual check. If there are any defects as
mentioned below, replace the steering pad with a
new one:
Cuts, minute cracks or marked ...
Changing engine switch modes
Modes can be changed by pressing the engine switch with the brake
pedal released. (The mode changes each time the switch is pressed.)
Off*
Emergency flashers can be used.
ACCESSORY mode
Some electrical components such
as the audio system can be used.
The engine switch indicator tu ...
If your vehicle has to
be stopped in an
emergency
Only in an emergency, such as if it becomes impossible to stop
the vehicle in the normal way, stop the vehicle using the following
procedure:
Steadily step on the brake pedal with both feet and firmly depress it.
Do not pump the brake pedal repeatedly as this will increase the effort
requi ...
