CRUISE CONTROL SYSTEM, Diagnostic DTC:P0571

DTC Code DTC Name
P0571 Stop Light Switch Circuit Malfunction

DESCRIPTION

When the brake pedal is depressed, the stop light switch sends a signal to the ECM. Upon receiving the signal, the ECM cancels cruise control. Even if there is a malfunction in the stop light signal circuit while cruise control is in operation, normal driving is maintained due to a fail-safe function.

When the brake pedal is depressed, positive voltage is applied to terminal STP of the ECM through the STOP fuse and stop light switch, and the ECM cancels cruise control.

DTC No.

Detection Item

DTC Detection Condition

Trouble Area

P0571

Stop Light Switch Circuit Malfunction

The voltages of terminals ST1- and STP of the ECM are both below 1 V for 0.5 seconds or more.

  • Stop light switch circuit

  • Stop light switch assembly

  • ECM

WIRING DIAGRAM

E195927E03

CAUTION / NOTICE / HINT

Note:

Inspect the fuses for circuits related to this system before performing the following inspection procedure.

PROCEDURE

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

    E182722C01

    *a

    Front view of wire harness connector

    (to Stop Light Switch Assembly)

    1. Disconnect the A5 stop light switch connector.

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

      Standard Voltage

      Tester Connection

      Condition

      Specified Condition

      A5-2 - Body ground

      Always

      11 to 14 V

      A5-4 - Body ground

      Engine switch on (IG)

      11 to 14 V

      A5-4 - Body ground

      Engine switch off

      Below 1 V

      Result

      Result

      OK

      NG
    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  2. INSPECT STOP LIGHT SWITCH ASSEMBLY

    1. E200528C02

      *1

      Pin

      *a

      Not Pushed

      *b

      Pushed

      Remove the stop light switch.

      Click here

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

    Standard Resistance

    Tester Connection

    Switch Condition

    Specified Condition

    1 - 2

    Not pushed

    Below 8.3 Ω

    1 - 2

    Pushed

    10 kΩ or higher

    3 - 4

    Pushed

    Below 1.6 Ω

    3 - 4

    Not pushed

    10 kΩ or higher

    Result

    Result

    OK

    NG
    NG

    REPLACE STOP LIGHT SWITCH

    OK

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

    1. Disconnect the A5 stop light switch connector.

    2. Disconnect the A5 stop light switch connector.

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

    Standard Resistance

    Tester Connection

    Condition

    Specified Condition

    A5-3 - G44-8 (ST1-)

    Always

    Below 1 Ω

    A5-1 - G45-18 (STP)

    Always

    Below 1 Ω

    A5-3 - Body ground

    Always

    10 kΩ or higher

    A5-1 - Body ground

    Always

    10 kΩ or higher

    Result

    Result

    OK

    NG
    OK

    REPLACE ECM

    Click here

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR