Airbag System Srs Warning Light Remains On

Restraints. Lexus Gs430, Gs300. Uzs190 Grs190
Supplemental Restraint System. Lexus Gs430, Gs300. Uzs190 Grs190

DESCRIPTION

WIRING DIAGRAM

INSPECTION PROCEDURE

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.
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 blinking 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 through the multiplex communication system.

WIRING DIAGRAM


Lexus Gs430, Gs300. Uzs190 Grs190.Supplemental Restraint System.Airbag System.Airbag System Srs Warning Light Remains On


INSPECTION PROCEDURE

1.CHECK BATTERY

  1. Measure the voltage of the battery.

    Voltage:
    11 to 14 V


NG
CHECK AND REPLACE BATTERY OR CHARGING SYSTEM
OK


2.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.

    OK:
    The connectors are connected.


NG
CONNECT CONNECTORS, THEN GO TO STEP 1
OK


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


    Lexus Gs430, Gs300. Uzs190 Grs190.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.

    Voltage:
    Tester connection
    		Condition
    		Specified condition
    L44-21 (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.

    Resistance:
    Tester connection
    		Condition
    		Specified condition
    L44-25 (E1) -
    Body ground
    		Always
    		Below 1 Ω
    L44-26 (E2) -
    Body ground
    		Always
    		Below 1 Ω


NG
REPAIR OR REPLACE WIRE HARNESS
OK


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


    Lexus Gs430, Gs300. Uzs190 Grs190.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.

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

    Voltage:
    Tester connection
    		Condition
    		Specified condition
    L31-1 (IG+) -
    Body ground
    		Engine switch on (IG)
    		10 to 14 V
    L31-22 (B) -
    Body ground
    		Always
    		10 to 14 V

  1. Turn the engine switch off.

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

    Resistance:
    Tester connection
    		Condition
    		Specified condition
    L31-28 (ES) -
    Body ground
    		Always
    		Below 1 Ω


NG
REPAIR OR REPLACE WIRE HARNESS
OK


5.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 connector to the combination meter.

  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:
    After the primary check period, SRS warning light goes off for approximately 10 seconds, and turning it on is continued.
    HINT:
    The primary check period shows approximately 6 seconds after the engine switch is turned on (IG).


NG
GO TO COMBINATION METER SYSTEM
OK

REPLACE CENTER AIRBAG SENSOR ASSEMBLY