LIN COMMUNICATION SYSTEM, Diagnostic DTC:U1129

DTC Code DTC Name
U1129 Lost Communication with Front Climate Control Seat ECU LH

DESCRIPTION

This DTC is output when LIN communication between the front seat climate control ECU LH and outer mirror switch stops for 10 seconds or more.

DTC Code DTC Detection Condition Trouble Area
U1129 No communication between front seat climate control ECU LH and outer mirror switch for 10 seconds or more

  • Front seat climate control ECU LH

  • Outer mirror switch

  • Wire harness

WIRING DIAGRAM

A01GHSTE13

INSPECTION PROCEDURE

Note


  • When using the intelligent tester with the engine switch off to troubleshoot:

    Connect the intelligent tester to the vehicle, and turn a courtesy switch on and off at 1.5 second intervals until communication between the tester and vehicle begins.

  • Inspect the fuses for circuits related to this system before performing the following inspection procedure.

Tech Tips

When DTC U1127, U1128 and U1129 are output simultaneously, perform troubleshooting for "Driver Side Switch Module LIN Communication Malfunction" first Click here.

PROCEDURE


  1. CLEAR DTC


    1. Delete the DTC Click here.


    NEXT

  2. CHECK FOR DTC


    1. Recheck for DTC Click here.

      Result:
      Result Proceed to
      DTC U1129 output reoccurs A
      DTC U1129 output does not reoccur B

    B

    USE SIMULATION METHOD TO CHECK Click here

    A

  3. CHECK HARNESS AND CONNECTOR (OUTER MIRROR SWITCH - FRONT SEAT CLIMATE CONTROL ECU LH)

    A01GJLZE01

    1. Disconnect the L6 switch connector.

    2. Disconnect the e34 ECU connector.

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

      Standard resistance
      Tester Connection Condition Specified Condition
      L6-7 (MPX) - e34-13 (LIN) Always Below 1 Ω
      L6-7 (MPX) or e34-13 (LIN) - Body ground Always 10 kΩ or higher

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  4. CHECK FRONT SEAT CLIMATE CONTROL ECU LH (BATTERY VOLTAGE AND GROUND)


    1. A01GNRSE03

      Disconnect the e34 ECU connector.

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

      Standard resistance
      Tester Connection Condition Specified Condition
      e34-12 (GND) - Body ground Always Below 1 Ω
      Standard voltage
      Tester Connection Condition Specified Condition
      e34-1 (IG) - Body ground Engine switch off Below 1 V
      e34-1 (IG) - Body ground Engine switch on (IG) 11 to 14 V
      e34-2 (SYSB) - Body ground Always 11 to 14 V

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  5. REPLACE FRONT SEAT CLIMATE CONTROL ECU LH


    1. Temporarily replace the front seat climate ECU LH with a new or normally functioning one.


    NEXT

  6. CHECK FOR DTC


    1. Delete the DTC Click here.

    2. Recheck for DTC Click here.

      Result:
      Result Proceed to
      DTC U1129 output does not reoccur A
      DTC U1129 output reoccurs B

    B

    REPLACE OUTER MIRROR SWITCH Click here

    A

    END (FRONT SEAT CLIMATE CONTROL ECU LH IS DEFECTIVE)