B1271

MULTIPLEX COMMUNICATION: MULTIPLEX COMMUNICATION SYSTEM: B1271: Combination Meter ECU Communication Stop

DTC B1271 - Combination Meter ECU Communication Stop

DESCRIPTION

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






WIRING DIAGRAM





INSPECTION PROCEDURE
HINT: When "+B or GND short malfunction of communication bus" DTCs (B1266 and B1267) are detected at the same time as "communication stop" DTC B1271, repair the "+B or GND short malfunction of communication bus" DTCs first.

PROCEDURE

1. INSPECT FUSE (DOME, ECU-B)
(a) Remove the DOME and ECU-B fuses from the fusible link block.
(b) Measure the resistance of the fuses.
Standard resistance:
Below 1 Ohms
NG -- REPLACE FUSE
OK -- Continue to next step.
2. CHECK WIRE HARNESS (COMBINATION METER ECU - BATTERY AND BODY GROUND)





(a) Disconnect the C8 and C9 ECU connectors.
(b) Measure the voltage and resistance of the wire harness side connector.
Standard voltage:






Standard resistance:






NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR
OK -- Continue to next step.
3. CHECK RESISTANCE OF COMMUNICATION LINE





(a) Disconnect the C8, C9, A20, G3 and C4 ECU connectors.
(b) Measure the resistance between the specified terminals on the wire harness side connectors.
Standard resistance:





HINT: *1: with LEXUS Navigation System
*2: without LEXUS Navigation System

Result:






C -- REPAIR OR REPLACE HARNESS OR CONNECTOR
B -- REPLACE COMBINATION METER ECU AND REPAIR OR REPLACE HARNESS OR CONNECTOR
OK -- REPLACE COMBINATION METER ECU