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:
Inspection
1. INSPECT STEERING PAD SWITCH LH (w/o
Navigation System)
Measure the resistance according to the values in
the table below.
Standard resistan
If the result is not as specified, replace the steering
pad switch LH.
2. INSPECT STEERING PAD SWITCH RH (w/ Navigation
System)
...
Removal
1. RECOVER REFRIGERANT FROM REFRIGERATION
SYSTEM (See page AC-172)
2. REMOVE NO. 2 AIR CLEANER INLET (See page EM-
28)
3. REMOVE FRONT BUMPER ASSEMBLY (See page
ET-3)
4. DISCONNECT DISCHARGE HOSE SUB-ASSEMBLY
(a) Remove the bolt and disconnect the discharge hose
sub-assembly from the coo ...
On-vehicle inspection
1. INSPECT FOR FUEL PUMP OPERATION AND FUEL
LEAK
(a) Check fuel pump operation.
(1) Connect the intelligent tester to the DLC3.
(2) Turn the engine switch on (IG) and push the
intelligent tester main switch on.
NOTICE:
Do not start the engine.
(3) Select the following menu it ...
