Dtc B1271 Combination Meter 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 (COMBINATION METER ASSEMBLY (METER ECU) - BATTERY AND BODY GROUND)

CHECK RESISTANCE OF COMMUNICATION LINE

DTC B1271 Combination Meter ECU Communication Stop


DESCRIPTION

This DTC is detected when communication between the combination meter (meter ECU) and network gateway ECU stops for more than 10 seconds.

DTC No.
DTC Detection Condition
Trouble Area
B1271
Combination meter ECU communication stops
  1. Combination meter assembly (meter ECU)
  2. Wire harness

WIRING DIAGRAM


Lexus Gs430, Gs300. Uzs190 Grs190.Multiplex Communication.Multiplex Communication System. Dtc B1271 Combination Meter Ecu Communication Stop


INSPECTION PROCEDURE

1.CHECK OPERATION

  1. Check that the tachometer operates properly while the engine is idling.

    OK:
    Tachometer operates properly while engine is idling.


NG
Go to step 2
OK

REPLACE COMBINATION METER ASSEMBLY (METER ECU)

2.CHECK (COMBINATION METER ASSEMBLY (METER ECU) - BATTERY AND BODY GROUND)
Lexus Gs430, Gs300. Uzs190 Grs190.Multiplex Communication.Multiplex Communication System. Dtc B1271 Combination Meter Ecu Communication Stop

  1. Disconnect the L31 meter connector.

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

    Standard Resistance:
    Tester Connection
    		Specified Condition
    L31-40 (E2) - Body ground
    		Below 1 Ω
    Standard Voltage:
    Tester Connection
    		Specified Condition
    L31-21 (B) - 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 B1271 Combination Meter Ecu Communication Stop

  1. Disconnect the L31and L66 ECU connectors.

  1. Disconnect the L44 sensor connector.

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

    Standard resistance:
    Tester Condition
    		Specified Condition
    L31-25 (MPX+) - L66-13 (MPI2)
    		Below 1 Ω
    L31-5 (MPX-) - L44-13 (MPX1)
    		Below 1 Ω
    Result:
    Result
    		Proceed to
    Both are OK
    		A
    One is OK
    		B
    Both are OK
    		C


B
REPLACE COMBINATION METER ASSEMBLY AND HARNESS AND CONNECTOR

C
REPAIR OR REPLACE HARNESS AND CONNECTOR
A

REPLACE COMBINATION METER ASSEMBLY (METER ECU)