Dtc B1280 Left Side Junction Block Ecu Communication Stop

Communication System. Lexus Is250, Is220D. Gse20 Ale20
Multiplex Communication. Lexus Is250, Is220D. Gse20 Ale20

DESCRIPTION

WIRING DIAGRAM

INSPECTION PROCEDURE

INSPECT FUSE (MPX-B)

CHECK WIRE HARNESS (MAIN BODY ECU 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 main body ECU LH (cowl side J/B LH) and gateway ECU stops for more than 10 seconds.

DTC No.
DTC Detection Condition
Trouble Area
B1280
Left side J/B ECU communication stops
  1. Main body ECU LH (cowl side J/B LH)
  2. Wire harness

WIRING DIAGRAM


Lexus Is250, Is220D. Gse20 Ale20.Multiplex Communication.Multiplex Communication System. Dtc B1280 Left Side Junction Block Ecu Communication Stop


Lexus Is250, Is220D. Gse20 Ale20.Multiplex Communication.Multiplex Communication System. Dtc B1280 Left Side Junction Block Ecu Communication Stop


INSPECTION PROCEDURE

HINT:
When "+B of GND short malfunction of communication bus" DTCs (B1214 and B1215) are detected at the same time as "communication stop" DTC B1280, repair the "+B or GND short malfunction of communication bus" DTCs first.
1.INSPECT FUSE (MPX-B)

  1. Remove the MPX-B from the engine room J/B No. 1.

  1. Measure the resistance of the fuse.

    Standard resistance:
    Below 1 Ω


NG
REPLACE FUSE
OK


2.CHECK WIRE HARNESS (MAIN BODY ECU LH - BATTERY AND BODY GROUND)


    Lexus Is250, Is220D. Gse20 Ale20.Multiplex Communication.Multiplex Communication System. Dtc B1280 Left Side Junction Block Ecu Communication Stop

  1. Disconnect the LD ECU connector.

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

    Standard voltage:
    Tester Connection
    		Condition
    		Specified Condition
    MPX-B (LD-18) - Body ground
    		Always
    		10 to 14 V
    Standard resistance:
    Tester Connection
    		Specified Condition
    GND (LD-3) - Body ground
    		Below 1 Ω


NG
REPAIR OR REPLACE HARNESS OR CONNECTOR
OK


3.CHECK RESISTANCE OF COMMUNICATION LINE

  1. Disconnect the Q3, A30, M7 and 2F ECU connectors (for LHD).



  1. Disconnect the Q3, A30, P33 and 2F ECU connectors (for RHD).


    Lexus Is250, Is220D. Gse20 Ale20.Multiplex Communication.Multiplex Communication System. Dtc B1280 Left Side Junction Block Ecu Communication Stop

  1. Measure the resistance between the specified terminals on the wire harness side connectors.

    Standard resistance:
    Tester Connection
    		Specified Condition
    *1MPX1 (Q3-15) - MPX1 (M7-7)
    *2MPX1 (Q3-15) - MPX2 (P33-28)
    		Below 1 Ω
    *1MPX2 (A30-17) - 2F-6
    *2MPX2 (A30-7) - 2F-6
    		Below 1 Ω
    HINT:
    1. *1: LHD
    2. *2: RHD
    Result:
    Result
    		Proceed to
    Both are OK
    		A
    One is OK
    		B
    Both are NG
    		C


B
REPAIR OR REPLACE HARNESS OR CONNECTOR AND REPLACE MAIN BODY ECU LH

C
REPAIR OR REPLACE HARNESS OR CONNECTOR
A

REPLACE MAIN BODY ECU LH (COWL SIDE J/B LH)