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.





HINT
For vehicles with climate control seat system only.

WIRING DIAGRAM





INSPECTION PROCEDURE

NOTICE:
When using the Techstream with the engine 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 Techstream 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.

OK:

DTC U1129 is not output.

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

OK -- USE SIMULATION METHOD TO CHECK How To Proceed With Troubleshooting

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

(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 FRONT SEAT CLIMATE CONTROL ECU LH (BATTERY VOLTAGE AND 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 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.

OK:

DTC U1129 is not output.

NG -- REPLACE OUTER MIRROR SWITCH Removal

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