B1280

MULTIPLEX COMMUNICATION: MULTIPLEX COMMUNICATION SYSTEM: B1280: Left Side Junction Block ECU Communication Stop
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 network gateway ECU stops for more than 10 seconds.





WIRING DIAGRAM





INSPECTION PROCEDURE

HINT
When "+B or 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.

PROCEDURE

1. INSPECT FUSE (MPX-B)

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

(b) Measure the resistance of the fuse.

Standard resistance:

Below 1 Ohms

NG -- REPLACE FUSE
OK -- Continue to next step.

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

(a) Disconnect the LD ECU connector.





(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 Q3, A30, M17 and 2F ECU connectors.





(b) Measure the resistance between the specified terminals on the wire harness side connectors.

Standard resistance:





Result:





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