AIRBAG SYSTEM Source Voltage Drop

DESCRIPTION

The SRS is equipped with a voltage-increase circuit (DC-DC converter) in the airbag ECU assembly in case the source voltage drops.

When the battery voltage drops, the voltage-increase circuit (DC-DC converter) functions to increase voltage of the SRS to normal voltage.

The diagnosis system malfunction display for this circuit is different from other circuits that is when the SRS warning light remains lit up and the DTC is a normal code, source voltage drop is indicated.

Malfunction in this circuit is not recorded in the airbag ECU assembly, and the source voltage returns to normal, the SRS warning light automatically goes off.

DTC No. Diagnosis
(Normal) Source voltage drop

WIRING DIAGRAM

A01KI32E01

INSPECTION PROCEDURE

PROCEDURE


  1. PREPARE FOR INSPECTION


    1. Disconnect negative (-) terminal cable from the battery, and wait at least for 90 seconds.

    2. Remove the horn button assembly Click here.

    3. Disconnect the seat belt pretensioner connectors Click here.

    4. Disconnect the connectors of the airbag ECU assembly Click here.

    5. Disconnect the connector of the airbag sensor assembly No. 2 Click here.

      CAUTION:

      Store the horn button assembly with the front surface facing upward.

  2. CHECK SOURCE VOLTAGE


    1. A01KF98E01

      Connect negative (-) terminal cable to the battery turn the ignition switch to ON, and at least for 60 seconds.

    2. Measure the voltage between body ground and each of IG1 and IG2 on the sensor and operate electric system (defogger, wiper, headlight, heater blower, etc.).

      OK
      Voltage: 10 - 14 V

    NG

    REPAIR OR REPLACE HARNESS BETWEEN BATTERY AND AIRBAG SENSOR ASSEMBLY, AND CHARGING SYSTEM

    OK

  3. CHECK SRS WARNING LIGHT TURN OFF


    1. Turn the ignition switch to LOCK.

    2. Disconnect negative (-) terminal cable from the battery, and wait at least for 90 seconds.

    3. Connect the horn button assembly connector.

    4. Connect the seat belt pretensioner connectors.

    5. Connect the airbag ECU assembly connector.

    6. Connect the airbag sensor assembly No. 2.

    7. Connect negative (-) terminal cable to the battery.

    8. Turn the ignition switch to ON, and wait at least for 60 seconds.

    9. Operate electric system (defogger, wiper, headlight, heater blower, etc.) and check that SRS warning light goes off.

      OK
      SRS warning Light is not Lights up.

    NG

    REPAIR OR REPLACE HARNESS BETWEEN BATTERY AND AIRBAG SENSOR ASSEMBLY, AND CHARGING SYSTEM

    OK

  4. CHECK AIR BAG ECU ASSEMBLY

    SST
    09843-18040

    1. Turn the ignition switch to LOCK.

    2. Disconnect negative (-) terminal cable from the battery, and wait at least for 90 seconds.

    3. Connect the airbag ECU assembly connector.

    4. Connect negative (-) terminal cable to the battery, and wait at least for 2 seconds.

    5. Turn the ignition switch to ON, and wait at least for 20 seconds.

    6. Clear the DTC stored in memory Click here.

    7. Turn the ignition switch to LOCK, and wait at least for 20 seconds.

    8. Turn the ignition switch to ON, and wait at least for 60 seconds.

    9. Check the DTC Click here.

      OK
      DTC is not output.

    NG

    REPLACE AIR BAG ECU ASSEMBLY

    OK

    USE SIMULATION METHOD TO CHECK