Dtc P0571 Brake Switch A Circuit

Cruise Control System. Camry. Acv40 Gsv40
Cruise Control. Camry. Acv40 Gsv40

DESCRIPTION

WIRING DIAGRAM

INSPECTION PROCEDURE

READ VALUE ON INTELLIGENT TESTER

CHECK HARNESS AND CONNECTOR (STOP LIGHT SWITCH - BATTERY)

INSPECT STOP LIGHT SWITCH

CHECK ECM

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
When voltage of STP terminal and that of ST1- terminal of ECM are less than 1 V for 0.5 sec. or more
  1. Stop light switch
  2. Stop light switch circuit
  3. ECM

WIRING DIAGRAM


Camry. Acv40 Gsv40.Cruise Control.Cruise Control System. Dtc P0571 Brake Switch A Circuit


INSPECTION PROCEDURE

1.READ VALUE ON INTELLIGENT TESTER

  1. Connect the intelligent tester to the DLC3.

  1. Turn the ignition switch to the ON position, and turn the intelligent tester main switch on.

  1. Check the DATA LIST for proper functioning of the stop light switch.

    ECM (Cruise control):
    Item
    		Measurement Item / Display (Range)
    		Normal Condition
    		Diagnostic Note
    Stp Light SW M
    		Stop light switch signal (Main CPU) / ON or OFF
    		ON: Brake pedal depressed
    OFF: Brake pedal released
    		-
    OK:
    When the brake pedal is operated, the display changes as shown above.


OK
REPLACE ECM
NG


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


    Camry. Acv40 Gsv40.Cruise Control.Cruise Control System. Dtc P0571 Brake Switch A Circuit

  1. Disconnect the A19 connector from the stop light switch.

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

    Standard voltage:
    Tester Connection
    		Condition
    		Specified Condition
    A19-2 - Body ground
    		Always
    		10 to 14 V
    A19-3 - Body ground
    		Ignition switch ON
    		10 to 14 V


NG
REPAIR OR REPLACE HARNESS OR CONNECTOR
OK


3.INSPECT STOP LIGHT SWITCH


    Camry. Acv40 Gsv40.Cruise Control.Cruise Control System. Dtc P0571 Brake Switch A Circuit

  1. Remove the stop light switch. (CAMRY_ACV40 RM0000022KA00OX.html)

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

    Standard resistance:
    Tester Connection
    		Switch Condition
    		Specified Condition
    1 - 2
    		Switch pin not pushed
    		Below 1 Ω
    3 - 4
    		Switch pin not pushed
    		10 kΩ or higher
    1 - 2
    		Switch pin pushed
    		10 kΩ or higher
    3 - 4
    		Switch pin pushed
    		Below 1 Ω

  1. Install the stop light switch.



NG
REPLACE STOP LIGHT SWITCH
OK


4.CHECK ECM


    Camry. Acv40 Gsv40.Cruise Control.Cruise Control System. Dtc P0571 Brake Switch A Circuit

  1. Reconnect the stop light switch connector.

  1. Disconnect the A55 connector from the ECM. (2GR-FE (LHD))

  1. Disconnect the A24 connector from the ECM. (2AZ-FE, 2GR-FE (RHD))

  1. Turn the ignition switch to the ON position.

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

    Standard voltage:
    Tester Connection
    		Brake Pedal Condition
    		Specified Condition
    A55-36 (STP) - Body ground*1
    A24-36 (STP) - Body ground*2
    		Depressed
    		10 to 14 V
    A55-36 (STP) - Body ground*1
    A24-36 (STP) - Body ground*2
    		Released
    		Below 1 V
    A55-35 (ST1-) - Body ground*1
    A24-35 (ST1-) - Body ground*2
    		Depressed
    		Below 1 V
    A55-35 (ST1-) - Body ground*1
    A24-35 (ST1-) - Body ground*2
    		Released
    		10 to 14 V
    HINT:
    *1: 2GR-FE (LHD)
    *2: 2AZ-FE, 2GR-FE (RHD)


NG
REPAIR OR REPLACE HARNESS OR CONNECTOR (STOP LIGHT SWITCH - ECM)
OK

REPLACE ECM