Dtc B1272 Power Seat 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 (POSITION CONTROL ECU AND SWITCH ASSEMBLY (DRIVER SEAT ECU) - BATTERY AND BODY GROUND)

CHECK RESISTANCE OF COMMUNICATION LINE

DTC B1272 Power Seat ECU Communication Stop


DESCRIPTION

This DTC is detected when communication between the position control ECU and switch (driver seat ECU) and network gateway ECU stops for more than 10 seconds.

DTC No.
DTC Detection Condition
Trouble Area
B1272
Position control ECU and switch assembly communication stops
  1. Position control ECU and switch assembly (driver seat ECU)
  2. Wire harness

WIRING DIAGRAM


Lexus Gs430, Gs300. Uzs190 Grs190.Multiplex Communication.Multiplex Communication System. Dtc B1272 Power Seat Ecu Communication Stop


Lexus Gs430, Gs300. Uzs190 Grs190.Multiplex Communication.Multiplex Communication System. Dtc B1272 Power Seat Ecu Communication Stop


INSPECTION PROCEDURE

1.CHECK OPERATION

  1. Check that the manual switch of the front power seat can move the driver side seat normally.

    OK:
    Manual switch of front power seat can move driver side seat normally.


NG
Go to step 2
OK

REPLACE POSITION CONTROL ECU AND SWITCH ASSEMBLY (DRIVER SEAT ECU)

2.CHECK WIRE HARNESS (POSITION CONTROL ECU AND SWITCH ASSEMBLY (DRIVER SEAT ECU) - BATTERY AND BODY GROUND)

Lexus Gs430, Gs300. Uzs190 Grs190.Multiplex Communication.Multiplex Communication System. Dtc B1272 Power Seat Ecu Communication Stop

  1. Disconnect the d8*1, c6*2 and d7*1, c7*2 ECU connectors.

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

    Standard Resistance:
    Tester Connection
    		Specified Condition
    d8-1 (GND)*1 - Body ground
    		Below 1 Ω
    c6-1 (GND)*2 - Body ground
    		Below 1 Ω
    Standard Voltage:
    Tester Connection
    		Specified Condition
    d7-8 (SYSB)*1 - Body ground
    		10 to 14 V
    c7-8 (SYSB)*2 - 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 B1272 Power Seat Ecu Communication Stop

  1. Disconnect the d7*1, c7*2 and W3*1, L31*2, L45*2 ECU connectors.

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

    Standard resistance:
    Tester Connection
    		Specified Condition
    d7-1 (MPX1)*1 - W3-15 (MPX1)*1
    		Below 1 Ω
    c7-1 (MPX1)*2 - L31-5 (MPX-)*2
    		Below 1 Ω
    c7-1 (MPX1)*2 - L45-6 (MPX1)*2
    		Below 1 Ω


NG
REPAIR OR REPLACE HARNESS AND CONNECTOR
OK

REPLACE POSITION CONTROL ECU AND SWITCH ASSEMBLY