U1128

MULTIPLEX COMMUNICATION: LIN COMMUNICATION SYSTEM: U1128: Lost Communication with Front Climate Control Seat ECU RH

DTC U1128 - Lost Communication with Front Climate Control Seat ECU RH

DESCRIPTION

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






WIRING DIAGRAM





INSPECTION PROCEDURE
NOTE:
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 U1128 is not output.
NG -- CHECK HARNESS AND CONNECTOR (OUTER MIRROR SWITCH - FRONT SEAT CLIMATE CONTROL ECU RH)
OK -- USE SIMULATION METHOD TO CHECK
3. CHECK HARNESS AND CONNECTOR (OUTER MIRROR SWITCH - FRONT SEAT CLIMATE CONTROL ECU RH)




(a) Disconnect the L6 switch connector.
(b) Disconnect the e4 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 RH (BATTERY VOLTAGE AND GROUND)




(a) Disconnect the e4 ECU connector.
(b) Measure the resistance and voltage according to the value(s) in the table below.
Standard voltage:






Standard resistance:






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

5. REPLACE FRONT SEAT CLIMATE ECU RH
(a) Temporarily replace the front seat climate ECU RH with a new or normally functioning one.
(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 U1128 is not output.
NG -- REPLACE OUTER MIRROR SWITCH
OK -- END (FRONT SEAT CLIMATE CONTROL ECU RH IS DEFECTIVE)