Airbag System Srs Warning Light Remains On

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

DESCRIPTION

WIRING DIAGRAM

INSPECTION PROCEDURE

CHECK CAN COMMUNICATION SYSTEM

CHECK MULTIPLEX COMMUNICATION SYSTEM

CHECK BATTERY

CHECK CONNECTORS

CHECK WIRE HARNESS (SOURCE VOLTAGE OF CENTER AIRBAG SENSOR ASSEMBLY)

CHECK WIRE HARNESS (SOURCE VOLTAGE OF COMBINATION METER)

CHECK SRS WARNING LIGHT

AIRBAG SYSTEM - SRS Warning Light Remains ON


DESCRIPTION

The SRS warning light is located on the combination meter assembly.
When the SRS is normal, the SRS warning light comes on for approximately 6 seconds after the engine switch is turned from off to on (IG), and then goes off automatically.
If there is a malfunction in the SRS, the SRS warning light comes on to inform the driver of a problem.
When terminals TC and CG of the DLC3 are connected, the DTC is displayed by blinking of the SRS warning light.
The SRS is equipped with a voltage-increase circuit (DC-DC converter) in the center airbag sensor assembly in case the source voltage drops.
When the battery voltage drops, the voltage-increase circuit (DC-DC converter) functions to increase the voltage of the SRS to normal voltage.
A malfunction in this circuit is not recorded in the center airbag sensor assembly. The SRS warning light automatically goes off when the source voltage returns to normal.
The signal to illuminate the SRS warning light is transmitted from the center airbag sensor assembly to the combination meter assembly through the CAN communication system and the multiplex communication system.

WIRING DIAGRAM


Lexus Is250, Is220D. Gse20 Ale20.Supplemental Restraint System.Airbag System.Airbag System Srs Warning Light Remains On


Lexus Is250, Is220D. Gse20 Ale20.Supplemental Restraint System.Airbag System.Airbag System Srs Warning Light Remains On


Lexus Is250, Is220D. Gse20 Ale20.Supplemental Restraint System.Airbag System.Airbag System Srs Warning Light Remains On


INSPECTION PROCEDURE

1.CHECK CAN COMMUNICATION SYSTEM

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

    Result:

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


B
REPAIR CIRCUITS INDICATED BY OUTPUT DTCS
A


2.CHECK MULTIPLEX COMMUNICATION SYSTEM

  1. Check if the MULTIPLEX communication DTC is output (Click here).

    Result:

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


B
REPAIR CIRCUITS INDICATED BY OUTPUT DTCS
A


3.CHECK BATTERY

  1. Measure the voltage of the battery.

    Standard voltage:
    11 to 14 V


NG
CHECK AND REPLACE BATTERY OR CHARGING SYSTEM
OK


4.CHECK CONNECTORS

  1. Turn the engine switch off.

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

  1. Check that the connectors are properly connected to the center airbag sensor assembly and combination meter assembly.

    OK:
    The connectors are properly connected.


NG
CONNECT CONNECTORS, THEN GO TO STEP 1
OK


5.CHECK WIRE HARNESS (SOURCE VOLTAGE OF CENTER AIRBAG SENSOR ASSEMBLY)


    Lexus Is250, Is220D. Gse20 Ale20.Supplemental Restraint System.Airbag System.Airbag System Srs Warning Light Remains On

  1. Disconnect the connectors from the center airbag sensor assembly.

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

  1. Turn the engine switch on (IG).

  1. Operate all components of the electrical system (defogger, wipers, headlight, heater blower, etc.).

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

    Standard voltage:
    Tester connection
    		Condition
    		Specified condition
    J47-21 (IG2) - Body ground
    		Engine switch on (IG)
    		10 to 14 V

  1. Turn the engine switch off.

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

    Standard resistance:
    Tester connection
    		Condition
    		Specified condition
    J47-25 (E1) - Body ground
    		Always
    		Below 1 Ω
    J47-26 (E2) - Body ground
    		Always
    		Below 1 Ω


NG
REPAIR OR REPLACE WIRE HARNESS
OK


6.CHECK WIRE HARNESS (SOURCE VOLTAGE OF COMBINATION METER)


    Lexus Is250, Is220D. Gse20 Ale20.Supplemental Restraint System.Airbag System.Airbag System Srs Warning Light Remains On

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

  1. Disconnect the connector from the combination meter assembly.

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

  1. Turn the engine switch on (IG).

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

    Standard voltage:
    Tester connection
    		Condition
    		Specified condition
    J34-12 (IG+) - Body ground
    		Engine switch on (IG)
    		10 to 16 V
    J34-23 (B) - Body ground
    		Always
    		10 to 16 V
    J34-24 (B) - Body ground
    		Always
    		10 to 16 V

  1. Turn the engine switch off.

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

    Standard resistance:
    Tester connection
    		Condition
    		Specified condition
    J34-1 (E2) - Body ground
    		Always
    		Below 1 Ω
    J34-13 (ES) - Body ground
    		Always
    		Below 1 Ω


NG
REPAIR OR REPLACE WIRE HARNESS
OK


7.CHECK SRS WARNING LIGHT

  1. Turn the engine switch off.

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

  1. Connect the J34 connector to the combination meter assembly.

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

  1. Turn the engine switch on (IG).

  1. Check the SRS warning light condition.

    OK:
    The SRS warning light turns on approximately 10 seconds after turning the engine switch on (IG).
    HINT:
    The primary check period is approximately 6 seconds after the engine switch is turned on (IG).


NG
GO TO COMBINATION METER SYSTEM
OK

REPLACE CENTER AIRBAG SENSOR ASSEMBLY