Dtc B1280 Left Side Junction Block Ecu Communication Stop

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

DESCRIPTION

WIRING DIAGRAM

INSPECTION PROCEDURE

CHECK FUSE (MPX-B, D/C CUT)

CHECK WIRE HARNESS (COWL SIDE JUNCTION BLOCK LH - BATTERY AND BODY GROUND)

CHECK RESISTANCE OF COMMUNICATION LINE

DTC B1280 Left Side Junction Block ECU Communication Stop


DESCRIPTION

This DTC is detected when communication between the multiplex network body ECU (cowl side junction block ECU LH) and network gateway ECU stops for more than 10 seconds.

DTC No.
DTC Detection Condition
Trouble Area
B1280
Cowl side junction block ECU LH communication stops
  1. Multiplex network body ECU (cowl side junction block ECU LH)
  2. Wire harness

WIRING DIAGRAM


Lexus Gs430, Gs300. Uzs190 Grs190.Multiplex Communication.Multiplex Communication System. Dtc B1280 Left Side Junction Block Ecu Communication Stop


INSPECTION PROCEDURE

1.CHECK FUSE (MPX-B, D/C CUT)

  1. Remove the MPX-B from the engine room No. 1 relay block.

  1. Measure the resistance of the fuses.

    Standard:
    Below 1 Ω


NG
REPLACE FUSE
OK


2.CHECK WIRE HARNESS (COWL SIDE JUNCTION BLOCK LH - BATTERY AND BODY GROUND)

Lexus Gs430, Gs300. Uzs190 Grs190.Multiplex Communication.Multiplex Communication System. Dtc B1280 Left Side Junction Block Ecu Communication Stop

  1. Disconnect the PL and PA J/B connectors.

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

    Standard resistance:
    Tester Connection
    		Specified Condition
    PA-14 (GND) - Body ground
    		Below 1 Ω
    Standard voltage:
    Tester Connection
    		Specified Condition
    PL-1 (MPXB) - Body ground
    		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 B1280 Left Side Junction Block Ecu Communication Stop

  1. Disconnect the W3 ECU connector.

  1. Disconnect the LC J/B connector.

  1. Disconnect the d7 switch connector.

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

    Standard resistance:
    Tester Connection
    		Specified Condition
    W3-15 (MPX1) - LC-31 (MPX2)
    		Below 1 Ω
    W3-15 (MPX1) - d7-1 (MPX1)
    		Below 1 Ω
    Result:
    Result
    		Proceed to
    Both are OK
    		A
    One is OK
    		B
    Both are NG
    		C


B
REPLACE COWL SIDE JUNCTION BLOCK LH AND HARNESS AND CONNECTOR

C
REPAIR OR REPLACE HARNESS AND CONNECTOR
A

REPLACE COWL SIDE JUNCTION BLOCK LH