Dtc B1281 Airbag Ecu Communication Stop

Communication System. Lexus Gs430, Gs300. Uzs190 Grs190
Multiplex Communication. Lexus Gs430, Gs300. Uzs190 Grs190

DESCRIPTION

WIRING DIAGRAM

INSPECTION PROCEDURE

CHECK OPERATION

CHECK WIRE HARNESS (CENTER AIRBAG SENSOR ASSEMBLY - BATTERY AND BODY GROUND)

CHECK RESISTANCE OF COMMUNICATION LINE

DTC B1281 Airbag ECU Communication Stop


DESCRIPTION


HINT:
"Airbag ECU" refers to the center airbag sensor.
This DTC is detected when communication between the center airbag sensor and network gateway ECU stops for more than 10 seconds.

DTC No.
DTC Detection Condition
Trouble Area
B1281
Center airbag sensor communication stops
  1. Center airbag sensor assembly
  2. Wire harness

WIRING DIAGRAM


Lexus Gs430, Gs300. Uzs190 Grs190.Multiplex Communication.Multiplex Communication System. Dtc B1281 Airbag Ecu Communication Stop


INSPECTION PROCEDURE

1.CHECK OPERATION

  1. Turn the engine switch on (IG) and check that the SRS warning light illuminates for approximately 6 seconds.

  1. Start the engine and check that the SRS warning light on the combination meter turns off.



NG
Go to step 2
OK

REPLACE AIRBAG SENSOR ASSEMBLY CENTER

2.CHECK WIRE HARNESS (CENTER AIRBAG SENSOR ASSEMBLY - BATTERY AND BODY GROUND)
Lexus Gs430, Gs300. Uzs190 Grs190.Multiplex Communication.Multiplex Communication System. Dtc B1281 Airbag Ecu Communication Stop

  1. Disconnect the L44 sensor connector.

  1. Measure the resistance and voltage of the wire harness side connector.

    Standard resistance:
    Tester Connection
    		Condition
    		Specified Condition
    L44-25 (E1) - Body ground
    		Always
    		Below 1 Ω
    Standard voltage:
    Tester Connection
    		Condition
    		Specified Condition
    L44-21 (IG2) - Body ground
    		Engine switch on (IG)
    		10 to 14 V


NG
REPAIR OR REPLACE HARNESS AND CONNECTOR
OK


3.CHECK RESISTANCE OF COMMUNICATION LINE

Lexus Gs430, Gs300. Uzs190 Grs190.Multiplex Communication.Multiplex Communication System. Dtc B1281 Airbag Ecu Communication Stop

  1. Disconnect the L44 sensor connector.

  1. Disconnect the L31 meter connector.

  1. Disconnect the L52 amplifier connector.

  1. Measure the resistance of the wire harness side connectors.

    Standard resistance:
    Tester Connection
    		Specified Condition
    L44-13 (MPX1) - L31-5 (MPX-)
    		Below 1 Ω
    L44-22 (MPX2) - L52-30 (MPX+)
    		Below 1 Ω
    Result:
    Result
    		Proceed to
    Both are OK
    		A
    One is OK
    		B
    Both are NG
    		C


B
REPLACE AIRBAG SENSOR ASSEMBLY CENTER AND HARNESS AND CONNECTOR

C
REPAIR OR REPLACE HARNESS AND CONNECTOR
A

REPLACE CENTER AIRBAG SENSOR ASSEMBLY