Dtc B1200 Mpx Body Ecu Stop

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

DESCRIPTION

WIRING DIAGRAM

INSPECTION PROCEDURE

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

CHECK WIRE HARNESS COWL SIDE JUNCTION BLOCK RH (MULTIPLEX NETWORK BODY ECU - BATTERY AND BODY GROUND)

CHECK RESISTANCE OF COMMUNICATION LINE

DTC B1200 MPX Body ECU Stop


DESCRIPTION

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

DTC No.
DTC Detection Condition
Trouble Area
B1200
Body ECU communication stops
  1. Cowl side junction block RH (cowl side junction block ECU RH)
  1. Wire harness

WIRING DIAGRAM


Lexus Gs430, Gs300. Uzs190 Grs190.Multiplex Communication.Multiplex Communication System. Dtc B1200 Mpx Body Ecu Stop


INSPECTION PROCEDURE

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

  1. Remove the MPX-B and D/C CUT fuses from the engine room No. 1 relay block.

  1. Measure the resistance of the fuses.

    Standard resistance:
    Below 1 Ω


NG
REPLACE FUSE
OK


2.CHECK WIRE HARNESS COWL SIDE JUNCTION BLOCK RH (MULTIPLEX NETWORK BODY ECU - BATTERY AND BODY GROUND)

Lexus Gs430, Gs300. Uzs190 Grs190.Multiplex Communication.Multiplex Communication System. Dtc B1200 Mpx Body Ecu Stop

  1. Disconnect the DA and DK junction block connectors.

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

    Standard voltage:
    Tester Connection
    		Specified Condition
    DK-5 (BECU) - Body ground
    		10 to 14 V
    Standard resistance:
    Tester Connection
    		Specified Condition
    DA-5 (GND2) - Body ground
    		Below 1 Ω


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 B1200 Mpx Body Ecu Stop

  1. Disconnect the DA junction block connector.

  1. Disconnect the L66, L68 and L27 ECU connectors.

  1. Disconnect the L22 switch connector.

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

    Standard resistance:
    Tester Connection
    		Specified Condition
    DA-26 (MPX1) - L66-14 (MPL2)
    		Below 1 Ω
    DA-20 (MPX1) - L27-5 (MPX1)
    		Below 1 Ω
    L68-21 (MPX2) - L22-6 (MPX1)
    		Below 1 Ω
    Result:
    Result
    		Proceed to
    All are OK
    		A
    One or two is / are OK
    		B
    All are NG
    		C


B
REPLACE COWL SIDE JUNCTION BLOCK RH (MULTIPLEX NETWORK BODY ECU) AND REPAIR OR REPLACE HARNESS AND CONNECTOR

C
REPAIR OR REPLACE HARNESS AND CONNECTOR
A

REPLACE COWL SIDE JUNCTION BLOCK RH (MULTIPLEX NETWORK BODY ECU)