MULTIPLEX COMMUNICATION SYSTEM, Diagnostic DTC:B1272

DTC Code DTC Name
B1272 Power Seat ECU Communication Stop

DESCRIPTION

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

DTC No. DTC Detection Condition Trouble Area
B1272 Front power seat switch (position control ECU) (driver seat ECU) communication stops

  • Front power seat switch (position control ECU) (driver seat ECU)

  • Wire harness or connector

WIRING DIAGRAM

A015ZD2E03
A015ZO0E06

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 B1272, perform troubleshooting for the "+B or GND short malfunction of communication bus" DTCs first Click here.

PROCEDURE


  1. INSPECT FUSE (FR P/SEAT LH*1, FR P/SEAT RH*2, MPX-B)


    1. Remove the FR P/SEAT LH fuse from the main body ECU LH (cowl side junction block LH)*1.

    2. Remove the FR P/SEAT RH fuse from the main body ECU RH (cowl side junction block RH)*2.

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

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      FR P/SEAT LH fuse*1 Always Below 1 Ω
      FR P/SEAT RH fuse*2 Always Below 1 Ω
      MPX-B fuse Always Below 1 Ω

      • *1: for LHD

      • *2: for RHD


    NG

    REPLACE FUSE

    OK

  2. CHECK HARNESS AND CONNECTOR (POSITION CONTROL ECU AND SWITCH - BATTERY AND BODY GROUND)


    1. A015ZISE07

      Disconnect the U6 and U7 ECU connectors*1.

    2. Disconnect the T6 and T7 ECU connectors*2.

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

      Standard Voltage
      Tester Connection Condition Specified Condition

      U7-8 (SYSB)*1 - Body ground

      T7-8 (SYSB)*2 - Body ground

      		 Always 11 to 14 V

      U6-5 (+B)*1 - Body ground

      T6-5 (+B)*2 - Body ground

      		 Always 11 to 14 V
      Standard Resistance
      Tester Connection Condition Specified Condition
      U6-1 (GND)*1 - Body ground Always Below 1 Ω
      T6-1 (GND)*2 - Body ground Always Below 1 Ω

      • *1: for LHD

      • *2: for RHD


    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR (FRONT POWER SEAT SWITCH - BATTERY AND BODY GROUND)

    OK

  3. CHECK HARNESS AND CONNECTOR (COMMUNICATION LINE)


    1. Disconnect the U7, 2F and J55 ECU connectors*1.

      A015Z90E05

    2. Disconnect the T7, L22 and P33 ECU connectors*2.

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

      Standard Resistance
      Tester Connection Condition Specified Condition

      U7-1 (MPX1)*1 - 2F-5 (MPX1)

      T7-1 (MPX1)*2 - L22-3 (MPX1)

      		 Always Below 1 Ω

      U7-1 (MPX1)*1 - J55-24 (MPX2)

      T7-1 (MPX1)*2 - P33-27 (MPX1)

      		 Always Below 1 Ω

      • *1: for LHD

      • *2: for RHD


    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR (COMMUNICATION LINE)

    OK

    REPLACE FRONT POWER SEAT SWITCH (POSITION CONTROL ECU) Click here