U1129

MULTIPLEX COMMUNICATION: LIN COMMUNICATION SYSTEM: U1129: Lost Communication with Front Climate Control Seat ECU LH
U1129 - Lost Communication with Front Climate Control Seat ECU LH

DESCRIPTION

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





WIRING DIAGRAM





INSPECTION PROCEDURE

NOTICE:
When using the Techstream with the power switch OFF to troubleshoot:

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

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

PROCEDURE

1. CLEAR DTC

(a) Clear the DTC Reading and Clearing Diagnostic Trouble Codes.

NEXT -- Continue to next step.

2. CHECK FOR DTC

(a) Recheck for DTC Reading and Clearing Diagnostic Trouble Codes.

Result





B -- USE SIMULATION METHOD TO CHECK How To Proceed With Troubleshooting
A -- Continue to next step.

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

(a) Disconnect the L6 switch connector.





(b) Disconnect the e34 ECU connector.

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

Standard resistance:





NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR
OK -- Continue to next step.

4. CHECK HARNESS AND CONNECTOR (SEAT CLIMATE CONTROL ECU - BATTERY AND BODY GROUND)

(a) Disconnect the e34 ECU connector.





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

Standard resistance:





Standard voltage:





NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR
OK -- Continue to next step.

5. REPLACE FRONT SEAT CLIMATE CONTROL ECU LH

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

except Ottoman: Disassembly

for Ottoman: Disassembly

(b) Clear the DTC Reading and Clearing Diagnostic Trouble Codes.

NEXT -- Continue to next step.

6. CHECK FOR DTC

(a) Recheck for DTC Reading and Clearing Diagnostic Trouble Codes.

Result





B -- REPLACE OUTER MIRROR SWITCH Removal

A -- END (FRONT SEAT CLIMATE CONTROL ECU LH IS DEFECTIVE)