LIN Communication System

MULTIPLEX COMMUNICATION: LIN COMMUNICATION SYSTEM: U1127: Lost Communication with Center Console Switch ECU

DTC U1127 - Lost Communication with Center Console Switch ECU

DESCRIPTION

This DTC is output when LIN communication between the outer mirror switch and No. 1 console switch stops for 10 seconds or more.






WIRING DIAGRAM





INSPECTION PROCEDURE
NOTE: When using the intelligent tester or Techstream with the power switch OFF to troubleshoot:

Connect the intelligent tester or 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
A -- Continue to next step.
3. CHECK HARNESS AND CONNECTOR (OUTER MIRROR SWITCH - NO. 1 CONSOLE SWITCH)





(a) Disconnect the L6 and L75 switch connectors.
(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.
4. CHECK HARNESS AND CONNECTOR (NO. 1 CONSOLE SWITCH - BATTERY AND BODY GROUND)





(a) Disconnect the L75 switch 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. CHECK NO. 1 CONSOLE SWITCH (OPERATION)
(a) Temporarily replace the No. 1 console switch 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.

Result:





B -- REPLACE OUTER MIRROR SWITCH
A -- END (NO. 1 CONSOLE SWITCH IS DEFECTIVE)