Airbag System Diagnosis Circuit

Restraints. Lexus Is250, Is220D. Gse20 Ale20
Supplemental Restraint System. Lexus Is250, Is220D. Gse20 Ale20

DESCRIPTION

WIRING DIAGRAM

INSPECTION PROCEDURE

CHECK CAN COMMUNICATION SYSTEM

CHECK WIRE HARNESS (DLC3 - ECM)

CHECK WIRE HARNESS (CG OF DLC3 - BODY GROUND)

CHECK WIRE HARNESS (TC OF ECM - BODY GROUND)

AIRBAG SYSTEM - Diagnosis Circuit


DESCRIPTION

DTC output mode is set by connecting terminals TC and CG of the DLC3.
DTCs are displayed by blinking the SRS warning light.
HINT:
  1. 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.
  2. A DTC output mode signal is transmitted through BEAN and CAN to each ECU including the center airbag sensor assembly, except for the skid control ECU with actuator. Thus when all systems except the VSC system do not enter DTC output mode, there may be an ECM malfunction.

WIRING DIAGRAM

  1. LHD:

    Lexus Is250, Is220D. Gse20 Ale20.Supplemental Restraint System.Airbag System.Airbag System Diagnosis Circuit


    Lexus Is250, Is220D. Gse20 Ale20.Supplemental Restraint System.Airbag System.Airbag System Diagnosis Circuit

  1. RHD:

    Lexus Is250, Is220D. Gse20 Ale20.Supplemental Restraint System.Airbag System.Airbag System Diagnosis Circuit


    Lexus Is250, Is220D. Gse20 Ale20.Supplemental Restraint System.Airbag System.Airbag System Diagnosis Circuit


INSPECTION PROCEDURE

1.CHECK CAN COMMUNICATION SYSTEM

  1. Check if the CAN communication system DTC is output (Click herefor LHD (gasoline), Click herefor LHD (diesel), Click herefor RHD (gasoline), or Click here for RHD (diesel)).

    Result:

    Condition
    		Proceed to
    DTC is not output
    		A
    DTC is output
    		B


B
REPAIR CIRCUITS INDICATED BY OUTPUT DTCS
A


2.CHECK WIRE HARNESS (DLC3 - ECM)


    Lexus Is250, Is220D. Gse20 Ale20.Supplemental Restraint System.Airbag System.Airbag System Diagnosis Circuit

  1. Turn the engine switch off.

  1. Disconnect the center airbag sensor assembly connector.

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

    Resistance:
    for Gasoline
    Tester connection
    		Condition
    		Specified condition
    J21-13 (TC) - A6-3 (TC)
    		Always
    		Below 1 Ω
    for Diesel
    Tester connection
    		Condition
    		Specified condition
    J21-13 (TC) - A49-26 (TC)
    		Always
    		Below 1 Ω


NG
REPAIR OR REPLACE WIRE HARNESS (TC OF DLC3 - TC OF ECM)
OK


3.CHECK WIRE HARNESS (CG OF DLC3 - BODY GROUND)


    Lexus Is250, Is220D. Gse20 Ale20.Supplemental Restraint System.Airbag System.Airbag System Diagnosis Circuit

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

    Standard resistance:
    Tester connection
    		Condition
    		Specified condition
    J21-4 (CG) - Body ground
    		Always
    		Below 1 Ω


NG
REPAIR OR REPLACE WIRE HARNESS (CG OF DLC3 - BODY GROUND)
OK


4.CHECK WIRE HARNESS (TC OF ECM - BODY GROUND)


    Lexus Is250, Is220D. Gse20 Ale20.Supplemental Restraint System.Airbag System.Airbag System Diagnosis Circuit

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

    Standard resistance:
    for Gasoline
    Tester connection
    		Condition
    		Specified condition
    A6-3 (TC) - Body ground
    		Always
    		1 MΩ or higher
    for Diesel
    Tester connection
    		Condition
    		Specified condition
    A49-26 (TC) - Body ground
    		Always
    		1 MΩ or higher


NG
REPAIR OR REPLACE WIRE HARNESS OR EACH ECU
OK

REPLACE CENTER AIRBAG SENSOR ASSEMBLY