MULTIPLEX COMMUNICATION SYSTEM, Diagnostic DTC:B1280

DTC Code DTC Name
B1280 Left Side Junction Block ECU Communication Stop

DESCRIPTION

This DTC is detected if communication between the main body ECU LH (cowl side junction block LH) and gateway ECU stops for more than 10 seconds.

DTC No. DTC Detection Condition Trouble Area
B1280 Left side junction block ECU communication stops

  • Main body ECU LH (cowl side junction block LH)

  • Wire harness or connector

WIRING DIAGRAM

A0161YKE04
A0161YKE05

INSPECTION PROCEDURE

Tech Tips

If "+B or GND short malfunction of communication bus" DTCs (B1214 and B1215) are detected at the same time as "communication stop" DTC B1280, perform troubleshooting for the "+B or GND short malfunction of communication bus" DTCs first Click here.

PROCEDURE


  1. INSPECT FUSE (MPX-B)


    1. Remove the MPX-B fuse from the engine room relay block No. 1.

    2. Measure the resistance according to the value(s) in the table below.

      Standard Resistance
      Tester Connection Condition Specified Condition
      MPX-B fuse Always Below 1 Ω

    NG

    REPLACE FUSE

    OK

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


    1. A01602ME01

      Disconnect the LD ECU connector.

    2. Measure the voltage and resistance according to the value(s) in the table below.

      Standard Voltage
      Tester Connection Condition Specified Condition
      LD-18 (MPXB) - Body ground Always 11 to 14 V
      Standard Resistance
      Tester Connection Condition Specified Condition
      LD-3 (GND) - Body ground Always Below 1 Ω

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR (MAIN BODY ECU LH - BATTERY AND BODY GROUND)

    OK

  3. CHECK HARNESS AND CONNECTOR


    1. Disconnect the Q3, A30, M20 and 2F ECU connectors*1.

      A0160FJE04

    2. Disconnect the Q3, A30, P33 and 2F ECU connectors*2.

    3. Measure the resistance according to the value(s) in the table below.

      Standard Resistance
      Tester Connection Condition Specified Condition

      Q3-15 (MPX1) - M20-3 (MPX1)*1

      Q3-15 (MPX1) - P33-28 (MPX2)*2

      		 Always Below 1 Ω

      A30-17 (MPX2) - 2F-6 (MPX2)*1

      A30-17 (MPX2) - 2F-6 (MPX2)*2

      		 Always Below 1 Ω

      • *1: for LHD

      • *2: for RHD


    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR (COMMUNICATION LINE)

    OK

    REPLACE MAIN BODY ECU LH (COWL SIDE JUNCTION BLOCK LH)