VEHICLE STABILITY CONTROL SYSTEM, Diagnostic DTC:C1380

DTC Code DTC Name
C1380 Stop Light Control Relay Malfunction

DESCRIPTION

Upon receiving the downhill assist control (for 4WD) or hill-start assist control operating signal from the skid control ECU, the relay contact turns on and the stop light comes on.

DTC Code DTC Detection Condition Trouble Area
C1380

Either of the following is detected:


  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 has not been input to the STP 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 is different from the input signal at the STP2 for 5 seconds or more.

  • Stop light switch

  • Stop light switch circuit

  • Stop light control relay

  • Stop light control relay circuit

  • Brake actuator assembly (Skid control ECU)

WIRING DIAGRAM

Refer to DTC C1425 Click here.

INSPECTION PROCEDURE

Note

When replacing the brake actuator assembly, perform zero point calibration Click here.

Tech Tips

When C1425 and/or C1426 is output together with C1380, inspect and repair the trouble areas indicated by C1425 and/or C1426 first Click here, or 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

    NG

    INSPECT STOP LIGHT CIRCUIT Click here

    OK

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


    1. Connect the intelligent tester to the DLC3.

    2. Turn the ignition switch on (IG).

    3. Select the Data List mode on the intelligent tester Click here.

      ABS / VSC / TRC:
      Tester Display Measurement Item/Range Normal Condition Diagnostic Note
      Stop Lamp SW Stop light switch / ON or OFF

      ON: Brake pedal depressed

      OFF: Brake pedal released

      		 -

    4. 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.

    NG

    INSPECT SKID CONTROL ECU (STP TERMINAL) Click here

    OK

  3. INSPECT SKID CONTROL ECU (STP2 TERMINAL)


    1. A017EHAE46

      Turn the ignition switch off.

    2. Make sure that there is no looseness at the locking part and the connecting part of the connector.

    3. Disconnect the skid control ECU connector.

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

      Standard resistance
      Tester Connection Condition Specified Condition
      A24-2 (STP) - A24-22 (STP2) Always Below 1 Ω

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR (STP2 CIRCUIT)

    OK

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


    1. Reconnect the skid control ECU connector.

    2. Connect the intelligent tester to the DLC3.

    3. Start the engine.

    4. Select the Active Test mode on the intelligent tester Click here.

      ABS / VSC / TRC:
      Tester Display Test Part Control Range Diagnostic Note
      Stop Lamp Relay Stop light control relay Relay ON / OFF Stop lights come on

    5. Check that the "ON" and "OFF" of the stop lights can be shown on the rear combination light by the intelligent tester.

      OK
      The stop lights turn on or off in accordance with the intelligent tester.

    NG

    INSPECT STOP LIGHT CONTROL RELAY Click here

    OK

  5. RECONFIRM DTC


    1. Turn the ignition switch off.

    2. Clear the DTCs Click here.

    3. Start the engine.

    4. Perform a road test.

    5. Check if the same DTC is recorded Click here.

      Result
      Result Proceed to
      DTC (C1380) is not output A
      DTC (C1380) is output B

    B

    REPLACE BRAKE ACTUATOR ASSEMBLY Click here

    A

    CHECK FOR INTERMITTENT PROBLEMS (SYMPTOM SIMULATION) Click here

  6. INSPECT STOP LIGHT CONTROL RELAY


    1. A017B3RE06

      Turn the ignition switch off.

    2. Remove the stop light control relay.

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

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

    NG

    REPLACE STOP LIGHT CONTROL RELAY

    OK

  7. INSPECT ENGINE ROOM RELAY BLOCK (POWER SOURCE TERMINAL)


    1. A017B02E01

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

      Standard voltage
      Tester Connection Condition Specified Condition
      Stop light control relay terminal 5 - Body ground Always 11 to 14 V
      Stop light control relay terminal 2 - Body ground Ignition switch on (IG) 11 to 14 V

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR (POWER SOURCE CIRCUIT)

    OK

  8. INSPECT SKID CONTROL ECU (STPO TERMINAL)


    1. A017EHAE47

      Install the stop light control relay.

    2. Make sure that there is no looseness at the locking part and the connecting part of the connector.

    3. Disconnect the skid control ECU connector.

    4. Turn the ignition switch on (IG).

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

      Standard voltage
      Tester Connection Switch Condition Specified Condition
      A24-31 (STPO) - Body ground Ignition switch on (IG) 11 to 14 V

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR (STPO CIRCUIT)

    OK

    REPLACE BRAKE ACTUATOR ASSEMBLY Click here

  9. INSPECT SKID CONTROL ECU (STP TERMINAL)


    1. A017EHAE44

      Turn the ignition switch off.

    2. Make sure that there is no looseness at the locking part and the connecting part of the connector.

    3. Disconnect the skid control ECU connector.

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

      Standard voltage
      Tester Connection Switch Condition Specified Condition
      A24-2 (STP) - Body ground Stop light switch ON (Brake pedal depressed) 8 to 14 V
      A24-2 (STP) - Body ground Stop light switch OFF (Brake pedal released) Below 1.5 V

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR (STP CIRCUIT)

    OK

    REPLACE BRAKE ACTUATOR ASSEMBLY Click here