ENTRY AND START SYSTEM, Diagnostic DTC:B2278

DTC Code DTC Name
B2278 Power Switch Circuit Malfunction

DESCRIPTION

This DTC is output when: 1) a malfunction is detected between the main body ECU and the power switch; or 2) either of the switches inside the power switch is malfunctioning.

DTC Code Detection Condition Trouble Area
B2278 Communication is abnormal between main body ECU and power switch or power switch is defective

  • Main body ECU

  • Power switch

  • Harness or connector

WIRING DIAGRAM

A000YHOE01
*a Power Switch
*b Main Body ECU (Driver Side Junction Block Assembly)

PROCEDURE


  1. READ VALUE USING INTELLIGENT TESTER (START SWITCH 1, 2)


    1. Use the Data List to check if the power switch is functioning properly.

      Main Body
      Tester Display Measurement Item/Range Normal Condition Diagnostic Note
      Start Switch 1 Start Switch 1/ON or OFF

      ON: Power switch ON (IG)

      OFF: Power switch OFF

      		 -
      Start Switch 2 Start Switch 2/ON or OFF

      ON: Power switch ON (IG)

      OFF: Power switch OFF

      		 -
      OK
      When the power switch is turned ON (IG), ON is displayed on the tester.

    NG

    INSPECT POWER SWITCH Click here

    OK

  2. CHECK POWER SWITCH (SWITCH CONDITION)


    1. Ensure the key is inside the cabin.

    2. With the brake pedal released, check that the power source mode changes as shown below each time the power switch is pushed.

      OK
      OFF → ON (ACC) → ON (IG) → OFF

    OK

    USE SIMULATION METHOD TO CHECK Click here

    NG

    GO TO ENTRY AND START SYSTEM (POWER SOURCE MODE DOES NOT CHANGE) Click here

  3. INSPECT POWER SWITCH

    A000TONE30
    *1 Component without harness connected: (Power Switch)

    1. Disconnect the L36 power switch connector.

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

      Standard resistance
      Tester Connection Switch Condition Specified Condition
      7 (SS1) - 5 (GND) Pushed Below 1 Ω
      2 (SS2) - 5 (GND) Pushed Below 1 Ω
      7 (SS1) - 5 (GND) Not pushed 10 kΩ or higher
      2 (SS2) - 5 (GND) Not pushed 10 kΩ or higher

    NG

    REPLACE POWER SWITCH Click here

    OK

  4. CHECK HARNESS AND CONNECTOR (MAIN BODY ECU - POWER SWITCH, BODY GROUND)

    A000U5DE04
    *1 Front view of wire harness connector: (to Main Body ECU)
    *2 Front view of wire harness connector: (to Power Switch)

    1. Disconnect the L13 main body ECU connector.

    2. Disconnect the L36 power switch connector.

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

      Standard resistance
      Tester Connection Condition Specified Condition
      L13-17 (SSW1) - L36-7 (SS1) Always Below 1 Ω
      L13-16 (SSW2) - L36-2 (SS2) Always Below 1 Ω
      L36-5 (GND) - Body ground Always Below 1 Ω
      L13-17 (SSW1) or L36-7 (SS1) - Body ground Always 10 kΩ or higher
      L13-16 (SSW2) or L36-2 (SS2) - Body ground Always 10 kΩ or higher

    OK

    REPLACE MAIN BODY ECU

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR