Dtc P0571 Stop Light Switch Circuit Malfunction

Engine Hybrid System. Land Cruiser. Urj200, 202 Grj200 Vdj200
Cruise Control. Land Cruiser. Urj200, 202 Grj200 Vdj200

DESCRIPTION

WIRING DIAGRAM

INSPECTION PROCEDURE

INSPECT FUSE (STOP, IGN, ECU-IG No. 2)

READ VALUE USING INTELLIGENT TESTER (STOP LIGHT SWITCH)

INSPECT BRAKE LIGHT RELAY (BRK LP)

CHECK HARNESS AND CONNECTOR (STOP LIGHT CONTROL RELAY - BATTERY AND BODY GROUND)

CHECK HARNESS AND CONNECTOR (STOP LIGHT CONTROL RELAY - STOP LIGHT SWITCH)

CHECK HARNESS AND CONNECTOR (STOP LIGHT CONTROL RELAY - BRAKE LIGHT RELAY)

CHECK STOP LIGHT CONTROL RELAY

CHECK HARNESS AND CONNECTOR (BRAKE LIGHT RELAY - BATTERY)

CHECK HARNESS AND CONNECTOR (BRAKE LIGHT RELAY, STOP LIGHT CONTROL RELAY - MASTER CYLINDER SOLENOID)

INSPECT STOP LIGHT SWITCH

CHECK HARNESS AND CONNECTOR (STOP LIGHT SWITCH - BATTERY)

CHECK HARNESS AND CONNECTOR (STOP LIGHT SWITCH - ECM)

DTC P0571 Stop Light Switch Circuit Malfunction


DESCRIPTION

The ECM receives the brake demand signal from the stop light switch and transmits it to the master cylinder solenoid (skid control ECU). The master cylinder solenoid (skid control ECU) receives the signal from the ECM and operates the brake actuator. 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 applied to terminal STP of the ECM through the STOP fuse and the stop light switch, and the ECM turns the cruise control off.

DTC Code
DTC Detection Condition
Trouble Area
P0571
  1. This trouble code is output when the ECM detects the brake light relay error signal from the master cylinder solenoid (skid control ECU) for 0.2 seconds. or more while the dynamic radar cruise control is in operation.
  2. When the voltage of the STP terminal and the ST1- terminal of the ECM is below than 1 V for 0.5 seconds. or more.
  1. Fuse (STOP, IGN, ECU-IG No. 2)
  2. Stop light switch
  3. Brake light relay
  4. Stop light control relay
  5. Master cylinder solenoid (skid control ECU)
  6. Harness or connector
  7. ECM

WIRING DIAGRAM


Land Cruiser. Urj200, 202 Grj200 Vdj200.Cruise Control.Cruise Control System. Dtc P0571 Stop Light Switch Circuit Malfunction


INSPECTION PROCEDURE

1.INSPECT FUSE (STOP, IGN, ECU-IG No. 2)

  1. Remove the STOP and IGN fuses from the engine room relay block.

  1. Remove the ECU-IG No. 2 fuse from the cowl side junction block LH.

  1. Measure the resistance according to the value(s) in the table below.

    Standard Resistance:
    Tester Connection
    		Condition
    		Specified Condition
    STOP fuse
    		Always
    		Below 1 Ω
    IGN fuse
    ECU-IG No. 2 fuse


NG
REPLACE FUSE
OK


2.READ VALUE USING INTELLIGENT TESTER (STOP LIGHT SWITCH)

  1. Using the intelligent tester, read the Data List (Click here).

    Radar Cruise
    Tester Display
    		Measurement Item/Range
    		Normal Condition
    		Diagnostic Note
    Stop Light SW M-CPU
    		Stop light switch signal (Main CPU) /
    ON or OFF
    		ON: Brake pedal depressed
    OFF: Brake pedal released
    		-
    OK:
    Normal conditions listed above are displayed.


NG
Go to step 10
OK


3.INSPECT BRAKE LIGHT RELAY (BRK LP)


    Land Cruiser. Urj200, 202 Grj200 Vdj200.Cruise Control.Cruise Control System. Dtc P0571 Stop Light Switch Circuit Malfunction

  1. Remove the brake light relay from the engine room relay block.

  1. Measure the resistance according to the value(s) in the table below.

    Standard Resistance:
    Tester Connection
    		Condition
    		Specified Condition
    3 - 4
    		Battery voltage is applied to terminals 1 and 2
    		10 kΩ higher
    Battery voltage is not applied to terminals 1 and 2
    		Below 1 Ω
    3 - 5
    		Battery voltage is not applied to terminals 1 and 2
    		10 kΩ higher
    Battery voltage is applied to terminals 1 and 2
    		Below 1 Ω


NG
REPLACE BRAKE LIGHT RELAY
OK


4.CHECK HARNESS AND CONNECTOR (STOP LIGHT CONTROL RELAY - BATTERY AND BODY GROUND)


    Land Cruiser. Urj200, 202 Grj200 Vdj200.Cruise Control.Cruise Control System. Dtc P0571 Stop Light Switch Circuit Malfunction

  1. Disconnect the A39 stop light control relay connector.

  1. Measure the voltage according to the value(s) in the table below.

    Standard Voltage:
    Tester Connection
    		Condition
    		Specified Condition
    A39-6 (+B) - Body ground
    		Always
    		11 to 14 V

  1. Measure the resistance according to the value(s) in the table below.

    Standard Resistance:
    Tester Connection
    		Condition
    		Specified Condition
    A39-4 (GND) - Body ground
    		Always
    		Below 1 Ω


NG
REPAIR OR REPLACE HARNESS OR CONNECTOR
OK


5.CHECK HARNESS AND CONNECTOR (STOP LIGHT CONTROL RELAY - STOP LIGHT SWITCH)


    Land Cruiser. Urj200, 202 Grj200 Vdj200.Cruise Control.Cruise Control System. Dtc P0571 Stop Light Switch Circuit Malfunction

  1. Disconnect the A39 stop light control relay connector.

  1. Disconnect the A30 stop light switch connector.

  1. Measure the resistance according to the value(s) in the table below.

    Standard Resistance:
    Tester Connection
    		Condition
    		Specified Condition
    A30-1 - A39-2 (STP)
    		Always
    		Below 1 Ω
    A30-1 - Body ground
    		Always
    		10 kΩ higher


NG
REPAIR OR REPLACE HARNESS OR CONNECTOR
OK


6.CHECK HARNESS AND CONNECTOR (STOP LIGHT CONTROL RELAY - BRAKE LIGHT RELAY)


    Land Cruiser. Urj200, 202 Grj200 Vdj200.Cruise Control.Cruise Control System. Dtc P0571 Stop Light Switch Circuit Malfunction

  1. Disconnect the A39 stop light control relay connector.

  1. Remove the brake light relay from the engine room relay block.

  1. Measure the resistance according to the value(s) in the table below.

    Standard Resistance:
    Tester Connection
    		Condition
    		Specified Condition
    A39-8 (OUT) - Brake light relay terminal 4
    		Always
    		Below 1 Ω
    A39-8 (OUT) - Body ground
    		Always
    		10 kΩ higher


NG
REPAIR OR REPLACE HARNESS OR CONNECTOR
OK


7.CHECK STOP LIGHT CONTROL RELAY


    Land Cruiser. Urj200, 202 Grj200 Vdj200.Cruise Control.Cruise Control System. Dtc P0571 Stop Light Switch Circuit Malfunction

  1. Remove the stop light control relay with its connector still connected (Click here ).

  1. Measure the voltage according to the value(s) in the table below.

    Standard Voltage:
    Tester Connection
    		Switch Condition
    		Specified Condition
    A39-6 (+B) - A39-4 (GND)
    		Always
    		11 to 14 V
    A39-2 (STP) - Body ground
    		Stop light switch on
    (Brake pedal depressed)
    		11 to 14 V
    Stop light switch off
    (Brake pedal released)
    		Below 1 V
    A39-8 (OUT) - Body ground
    		Stop light switch on
    (Brake pedal depressed)
    		11 to 14 V
    Stop light switch off
    (Brake pedal released)
    		Below 1 V


NG
REPLACE STOP LIGHT CONTROL RELAY (Click here)
OK


8.CHECK HARNESS AND CONNECTOR (BRAKE LIGHT RELAY - BATTERY)


    Land Cruiser. Urj200, 202 Grj200 Vdj200.Cruise Control.Cruise Control System. Dtc P0571 Stop Light Switch Circuit Malfunction

  1. Remove the brake light relay from the engine room relay block.

  1. Measure the voltage according to the value(s) in the table below.

    Standard Voltage:
    Tester Connection
    		Switch Condition
    		Specified Condition
    Brake light relay terminal 1 - Body ground
    		Engine switch on (IG)
    		11 to 14 V
    Brake light relay terminal 5 - Body ground
    		Always


NG
REPAIR OR REPLACE HARNESS OR CONNECTOR
OK


9.CHECK HARNESS AND CONNECTOR (BRAKE LIGHT RELAY, STOP LIGHT CONTROL RELAY - MASTER CYLINDER SOLENOID)


    Land Cruiser. Urj200, 202 Grj200 Vdj200.Cruise Control.Cruise Control System. Dtc P0571 Stop Light Switch Circuit Malfunction

  1. Disconnect the A24 master cylinder solenoid (skid control ECU) connector.

  1. Remove the brake light relay from the engine room relay block.

  1. Disconnect the A39 stop light control relay connector.

  1. Measure the resistance according to the value(s) in the table below.

    Standard Resistance:
    Tester Connection
    		Condition
    		Specified Condition
    Brake light relay terminal 2 - A24-16 (STP0)
    		Always
    		Below 1 Ω
    A39-2 (STP) - A24-45 (STP2)
    Brake light relay terminal 3 - A24-7 (STP)
    Brake light relay terminal 2 - Body ground
    		Always
    		10 kΩ higher
    A39-2 (STP) - Body ground
    Brake light relay terminal 3 - Body ground
    Result
    Result
    		Proceed to
    OK
    (for LHD)
    		A
    OK
    (for RHD)
    		B
    NG
    		C


B
REPLACE MASTER CYLINDER SOLENOID (SKID CONTROL ECU) (Click here)

C
REPAIR OR REPLACE HARNESS OR CONNECTOR
A

REPLACE MASTER CYLINDER SOLENOID (SKID CONTROL ECU) (Click here)

10.INSPECT STOP LIGHT SWITCH


    Land Cruiser. Urj200, 202 Grj200 Vdj200.Cruise Control.Cruise Control System. Dtc P0571 Stop Light Switch Circuit Malfunction

  1. Remove the stop light switch (Click here).

  1. Measure the resistance according to the value(s) in the table below.

    Standard Resistance:
    Tester Connection
    		Switch Condition
    		Specified Condition
    1 - 2
    		Pin not pushed
    		Below 1 Ω
    Pin pushed
    		10 kΩ higher
    3 - 4
    		Pin not pushed
    		10 kΩ higher
    Pin pushed
    		Below 1 Ω


NG
REPLACE STOP LIGHT SWITCH (Click here)
OK


11.CHECK HARNESS AND CONNECTOR (STOP LIGHT SWITCH - BATTERY)


    Land Cruiser. Urj200, 202 Grj200 Vdj200.Cruise Control.Cruise Control System. Dtc P0571 Stop Light Switch Circuit Malfunction

  1. Disconnect the A30 stop light switch connector.

  1. Measure the voltage according to the value(s) in the table below.

    Standard Voltage:
    Tester Connection
    		Switch Condition
    		Specified Condition
    A30-2 - Body ground
    		Engine switch on (IG)
    		11 to 14 V
    A30-4 - Body ground
    		Always


NG
REPAIR OR REPLACE HARNESS OR CONNECTOR
OK


12.CHECK HARNESS AND CONNECTOR (STOP LIGHT SWITCH - ECM)


    Land Cruiser. Urj200, 202 Grj200 Vdj200.Cruise Control.Cruise Control System. Dtc P0571 Stop Light Switch Circuit Malfunction

  1. Disconnect the A38*1 or A53*2 ECM connector.

    1. *1: for LHD
    2. *2: for RHD

  1. Disconnect the A30 stop light switch connector.

  1. Measure the resistance according to the value(s) in the table below.

    Standard Resistance:
    for LHD
    Tester Connection
    		Condition
    		Specified Condition
    A30-3 - A38-35 (ST1-)
    		Always
    		Below 1 Ω
    A30-1 - A38-36 (STP)
    A30-1 - Body ground
    		Always
    		10 kΩ higher
    A30-3 - Body ground
    for RHD
    Tester Connection
    		Condition
    		Specified Condition
    A30-3 - A53-35 (ST1-)
    		Always
    		Below 1 Ω
    A30-1 - A53-36 (STP)
    A30-1 - Body ground
    		Always
    		10 kΩ higher
    A30-3 - Body ground
Result
Result
Proceed to
OK (1UR-FE)
A
OK (3UR-FE)
B
NG
C


B
REPLACE ECM (Click here)

C
REPAIR OR REPLACE HARNESS OR CONNECTOR
A

REPLACE ECM (Click here)