AIRBAG SYSTEM Diagnosis Circuit

DESCRIPTION

DTC output mode is set by connecting terminals TC and CG of the DLC3.

DTCs are displayed by the blinking of the SRS warning light.

Tech Tips


  • When each warning light stays blinking, a ground short in the wiring of terminal TC of the DLC3 or an internal ground short in each ECU is suspected.

  • A DTC output mode signal is transmitted through CAN communication system to each ECU including the center airbag sensor assembly. Thus when all systems do not enter DTC output mode, there may be a hybrid vehicle control ECU malfunction.

WIRING DIAGRAM

A000WX8E03
*a Hybrid Vehicle Control ECU
*b Center Airbag Sensor Assembly
*c CAN Communication Line

PROCEDURE


  1. CHECK CAN COMMUNICATION SYSTEM


    1. for LHD:


      1. Check if a CAN communication system DTC is output Click here.

    2. for RHD:


      1. Check if a CAN communication system DTC is output Click here.

      Result
      Result Proceed to
      DTC is output (for LHD) A
      DTC is output (for RHD) B
      DTC is not output C

    A

    GO TO CAN COMMUNICATION SYSTEM Click here

    B

    GO TO CAN COMMUNICATION SYSTEM Click here

    C

  2. CHECK HARNESS AND CONNECTOR (DLC3 - HYBRID VEHICLE CONTROL ECU)

    A000X7NE02
    Front view of DLC3
    *1 Rear view of wire harness connector: (to Hybrid vehicle control ECU)

    1. Turn the power switch OFF.

    2. Disconnect the A77 hybrid vehicle control ECU connector.

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

      Standard resistance
      Tester Connection Condition Specified Condition
      L31-13 (TC) - A77-24 (TC) Always Below 1 Ω

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  3. CHECK HARNESS AND CONNECTOR (DLC3 - BODY GROUND)

    A000YO5E02
    *1 Front view of DLC3:

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

      Standard resistance
      Tester Connection Condition Specified Condition
      L31-4 (CG) - Body ground Always Below 1 Ω

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  4. CHECK HARNESS AND CONNECTOR (HYBRID VEHICLE CONTROL ECU - BODY GROUND)

    A000V4HE02
    *1 Rear view of wire harness connector: (to Hybrid vehicle control ECU)

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

      Standard resistance
      Tester Connection Condition Specified Condition
      A77-24 (TC) - Body ground Always 1 MΩ or higher

    OK

    REPLACE CENTER AIRBAG SENSOR ASSEMBLY Click here

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR OR EACH ECU