DYNAMIC RADAR CRUISE CONTROL SYSTEM, Diagnostic DTC:P0571

DTC Code DTC Name
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.

The skid control ECU receives a signal from the ECM and operates the brake actuator.

The skid control ECU operates the brake actuator and at the same time illuminates the stop light by operating the BRK-LP relay.

DTC No. DTC Detection Condition Trouble Area
P0571 This trouble code is output when the ECM detects the BRK-LP relay error signal from the skid control ECU for 0.2 sec. or more while the dynamic cruise control is in operation.

  • BRK-LP relay

  • BRK-LP relay circuit

  • Skid control ECU

WIRING DIAGRAM

A016320E01

INSPECTION PROCEDURE

PROCEDURE


  1. CHECK STOP LIGHT OPERATION


    1. Check that the stop lights come on when the brake pedal is depressed, and go off when the brake pedal is released.

      OK
      Condition Illumination Condition
      Brake pedal depressed ON
      Brake pedal released OFF

    NG

    GO TO PROBLEM SYMPTOMS TABLE (STOP LIGHT SYSTEM) Click here

    OK

  2. CHECK BRK-LP RELAY


    1. Turn the engine switch off.

    2. A0162XNE08

      Remove the BRK-LP relay from the engine room No. 3 relay block.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      3 - 5 Voltage is not applied between terminals 1 and 2 10 kΩ or higher
      3 - 5 Voltage is applied between terminals 1 and 2 Below 1 Ω
      3 - 4 Voltage is not applied between terminals 1 and 2 Below 1 Ω
      3 - 4 Voltage is applied between terminals 1 and 2 10 kΩ or higher

    NG

    REPLACE BRK-LP RELAY

    OK

  3. CHECK HARNESS AND CONNECTOR (ENGINE ROOM NO. 3 RELAY BLOCK - BATTERY)


    1. A0162YCE01

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

      Standard Voltage
      Tester Connection Condition Specified Condition
      BRK LP relay terminal 5 - Body ground Always 11 to 14 V
      BRK LP relay terminal 2 - Body ground Engine switch on (IG) 11 to 14 V
      BRK LP relay terminal 2 - Body ground Engine switch off Below 1 V

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  4. CHECK HARNESS AND CONNECTOR (ENGINE ROOM NO. 3 RELAY BLOCK - SKID CONTROL ECU)


    1. A01639YE02

      Disconnect the connector from the skid control ECU.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      A35*1, J98*2-21 (STPO) - BRK LP relay terminal 1 Always Below 1 Ω
      A35*1, J98*2-21 (STPO) - Body ground Always 10 kΩ or higher
      A35*1, J98*2-20 (STP2) - BRK LP relay terminal 4 Always Below 1 Ω
      A35*1, J98*2-20 (STP2) - Body ground Always 10 kΩ or higher

      • *1: for LHD

      • *2: for RHD


    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

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


    1. A0160YHE02

      Disconnect the connector from the stop light control relay.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      A35*1, J98*2-20 (STP2) - J96-2 (STP) Always Below 1 Ω
      A35*1, J98*2-20 (STP2) - Body ground Always 10 kΩ or higher

      • *1: for LHD

      • *2: for RHD


    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

    REPLACE SKID CONTROL ECU Click here