VEHICLE STABILITY CONTROL SYSTEM, Diagnostic DTC:C1380

DTC Code DTC Name
C1380 Stop Light Control Relay Malfunction

DESCRIPTION

Upon receiving the hill-start assist control operating signal from the skid control ECU, the relay contact turns on and the stop light comes on.

DTC No.

Detection Item

DTC Detection Condition

Trouble Area

C1380

Stop Light Control Relay Malfunction

Either condition is met:

  1. When the voltage at the IG1 terminal is between 10 and 14 V and the stop light control relay drive output (STPO) is on, a signal is not input to the STP2 terminal for 5 seconds or more.

  2. When the voltage at the IG1 terminal is between 10 and 14 V and the stop light control relay drive output (STPO) is off, the signal at the STP terminal is different from the input signal at the STP2 terminal for 5 seconds or more.

  • STOP fuse

  • Harness or connector

  • STOP LP relay

  • Stop light control relay

  • Master cylinder solenoid (Skid control ECU)

WIRING DIAGRAM

C220874E04

CAUTION / NOTICE / HINT

Note:

  • When replacing the master cylinder solenoid, perform calibration (Click here).

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

Tip:

When DTC C1425 is output together with DTC C1380, inspect and repair the trouble areas indicated by DTC C1425 first (Click here).

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

      Result

      Result

      OK

      NG
    NG

    CHECK TERMINAL VOLTAGE AND RESISTANCE (+B, GND)Click here

    OK

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

    1. Turn the engine switch off.

    2. Connect the intelligent tester to the DLC3.

    3. Turn the engine switch on (IG).

    4. Turn the intelligent tester on.

    5. Enter the following menus: Chassis / ABS/VSC/TRC / Data List.

      Chassis > ABS/VSC/TRC > Data List

      Tester Display

      Measurement Item

      Range

      Normal Condition

      Diagnostic Note

      Stop Light SW

      Stop light switch

      ON or OFF

      ON: Brake pedal depressed

      OFF: Brake pedal released

      -

    6. Check that the stop light switch condition observed on the intelligent tester changes according to brake pedal operation.

      OK

      The intelligent tester displays ON or OFF according to brake pedal operation.

      Result

      Result

      OK

      NG
    NG

    CHECK TERMINAL VOLTAGE (STP)Click here

    OK

  3. PERFORM ACTIVE TEST USING INTELLIGENT TESTER (STOP LIGHT RELAY)

    1. Turn the engine switch off.

    2. Connect the intelligent tester to the DLC3.

    3. Turn the engine switch on (IG).

    4. Turn the intelligent tester on.

    5. Enter the following menus: Chassis / ABS/VSC/TRC / Active Test.

      Chassis > ABS/VSC/TRC > Active Test

      Tester Display

      Measurement Item

      Control Range

      Diagnostic Note

      Stop Light Relay

      STOP LP relay

      Relay ON/OFF

      Observe the stop lights (do not come on for 2 to 5 seconds).

    6. While performing the Active Test, check the illumination condition of the stop lights and "Stop Light Relay Output" in the Data List.

      Chassis > ABS/VSC/TRC > Data List

      Tester Display

      Measurement Item

      Range

      Normal Condition

      Diagnostic Note

      Stop Light Relay Output

      STOP LP relay output

      ON or OFF

      ON: Relay output on (Stop lights on)

      OFF: Relay output off (Stop lights off)

      -

      Result

      Result

      Proceed to

      When Active Test performed, Data List item changes between ON and OFF and stop lights turn on and off

      A

      When Active Test performed, Data List item changes between ON and OFF, but stop lights do not turn on

      B
    B

    INSPECT STOP LP RELAYClick here

    A

  4. CHECK TERMINAL VOLTAGE (STP2)

    1. Disconnect the A7 skid control ECU connector.

    2. C214161C04

      *a

      Front view of wire harness connector

      (to Skid Control ECU)

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

      Standard Voltage

      Tester Connection

      Condition

      Specified Condition

      A7-45 (STP2) - Body ground

      Brake pedal depressed

      8 to 14 V

      Brake pedal released

      Below 1.5 V

      Result

      Result

      OK

      NG
    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  5. RECONFIRM DTC

    1. Clear the DTCs.

      Click here

      Chassis > ABS/VSC/TRC > Clear DTCs

    2. Start the engine.

    3. Perform a road test.

    4. Check if the same DTC is output.

      Click here

      Result

      Result

      Proceed to

      DTC is not output

      A

      DTC is output

      B

      Chassis > ABS/VSC/TRC > Trouble Codes

    A

    USE SIMULATION METHOD TO CHECK

    Click here

    B

    REPLACE MASTER CYLINDER SOLENOID

    Click here

  6. INSPECT STOP LP RELAY

    1. Remove the STOP LP relay from the engine room relay block.

    2. A087121C01

      *1

      STOP LP relay

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

      Standard Resistance

      Tester Connection

      Condition

      Specified Condition

      3 - 4

      Battery positive voltage is applied to terminal 1 and battery negative voltage is applied to terminal 2

      10 kΩ or higher

      Battery positive voltage is not applied to terminal 1 and battery negative voltage is not applied to terminal 2

      Below 1 Ω

      3 - 5

      Battery positive voltage is applied to terminal 1 and battery negative voltage is applied to terminal 2

      Below 1 Ω

      Battery positive voltage is not applied to terminal 1 and battery negative voltage is not applied to terminal 2

      10 kΩ or higher

      Result

      Result

      OK

      NG
    NG

    REPLACE STOP LP RELAY

    OK

  7. CHECK TERMINAL VOLTAGE (STOP LIGHT POWER SOURCE TERMINAL)

    1. Remove the STOP LP relay from the engine room relay block.

    2. C220884C01

      *a

      Component without STOP LP Relay

      (Engine Room Relay Block)

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

      Standard Voltage

      Tester Connection

      Switch Condition

      Specified Condition

      1 - Body ground

      Engine switch on (IG)

      8 to 14 V

      5 - Body ground

      Always

      11 to 14 V

      Result

      Result

      OK

      NG
    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  8. CHECK TERMINAL VOLTAGE (STPO)

    1. Disconnect the A7 skid control ECU connector.

    2. C214161C06

      *a

      *a

      Front view of wire harness connector

      (to Skid Control ECU)

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

      Standard Voltage

      Tester Connection

      Switch Condition

      Specified Condition

      A7-16 (STPO) - Body ground

      Engine switch on (IG)

      11 to 14 V

      Result

      Result

      OK

      NG
    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  9. RECONFIRM DTC

    1. Clear the DTCs.

      Click here

      Chassis > ABS/VSC/TRC > Clear DTCs

    2. Turn the engine switch off.

    3. Check if the same DTC is output.

      Click here

      Result

      Result

      Proceed to

      DTC is output

      A

      DTC is not output

      B

      Chassis > ABS/VSC/TRC > Trouble Codes

    A

    USE SIMULATION METHOD TO CHECK

    Click here

    B

    REPLACE MASTER CYLINDER SOLENOID

    Click here

  10. CHECK TERMINAL VOLTAGE (STP)

    1. Disconnect the A7 skid control ECU connector.

    2. C214161C05

      *a

      Front view of wire harness connector

      (to Skid Control ECU)

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

      Standard Voltage

      Tester Connection

      Condition

      Specified Condition

      A7-7 (STP) - Body ground

      Brake pedal depressed

      8 to 14 V

      Brake pedal released

      Below 1.5 V

      Result

      Result

      OK

      NG
    OK

    REPLACE MASTER CYLINDER SOLENOID

    Click here

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

  11. CHECK TERMINAL VOLTAGE AND RESISTANCE (+B, GND)

    1. Disconnect the A6 stop light control relay connector.

    2. C206543C01

      *a

      Front view of wire harness connector

      (to Stop Light Control Relay)

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

      Standard Voltage

      Tester Connection

      Condition

      Specified Condition

      A6-6 (+B) - Body ground

      Always

      11 to 14 V

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

      Standard Resistance

      Tester Connection

      Condition

      Specified Condition

      A6-4 (GND) - Body ground

      Always

      Below 1 Ω

      Result

      Result

      OK

      NG
    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  12. CHECK TERMINAL VOLTAGE (STP)

    1. Disconnect the A6 stop light control relay connector.

    2. C206543C02

      *a

      Front view of wire harness connector

      (to Stop Light Control Relay)

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

      Standard Voltage

      Tester Connection

      Condition

      Specified Condition

      A6-2 (STP) - Body ground

      Brake pedal depressed

      8 to 14 V

      Brake pedal released

      Below 1.5 V

      Result

      Result

      OK

      NG
    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  13. INSPECT STOP LP RELAY

    1. Remove the STOP LP relay from the engine room relay block.

    2. A087121C01

      *1

      STOP LP relay

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

      Standard Resistance

      Tester Connection

      Condition

      Specified Condition

      3 - 4

      Battery positive voltage is applied to terminal 1 and battery negative voltage is applied to terminal 2

      10 kΩ or higher

      Battery positive voltage is not applied to terminal 1 and battery negative voltage is not applied to terminal 2

      Below 1 Ω

      3 - 5

      Battery positive voltage is applied to terminal 1 and battery negative voltage is applied to terminal 2

      Below 1 Ω

      Battery positive voltage is not applied to terminal 1 and battery negative voltage is not applied to terminal 2

      10 kΩ or higher

      Result

      Result

      OK

      NG
    NG

    REPLACE STOP LP RELAY

    OK

  14. CHECK HARNESS AND CONNECTOR (STOP LIGHT CONTROL RELAY - STOP LP RELAY)

    1. Disconnect the A6 stop light control relay connector.

    2. Remove the STOP LP relay from the engine room relay block.

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

      Standard Resistance

      Tester Connection

      Condition

      Specified Condition

      A6-8 (OUT) - Engine room relay block STOP LP relay terminal 4

      Always

      Below 1 Ω

      A6-8 (OUT) - Body ground

      Always

      10 kΩ or higher

      Result

      Result

      OK

      NG
    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  15. CHECK TERMINAL VOLTAGE (STOP LIGHT POWER SOURCE TERMINAL)

    1. Remove the STOP LP relay from the engine room relay block.

    2. C220884C01

      *a

      Component without STOP LP Relay

      (Engine Room Relay Block)

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

      Standard Voltage

      Tester Connection

      Condition

      Specified Condition

      4 - Body ground

      Brake pedal depressed

      8 to 14 V

      Brake pedal released

      Below 1.5 V

      Result

      Result

      OK

      NG
    OK

    REPAIR OR REPLACE HARNESS OR CONNECTOR (ENGINE ROOM RELAY BLOCK STOP LP RELAY TERMINAL 3 CIRCUIT)

    NG

    REPLACE STOP LIGHT CONTROL RELAY ASSEMBLY

    Click here