U1131

MULTIPLEX COMMUNICATION: LIN COMMUNICATION SYSTEM: U1131: Lost Communication with Rear Climate Control Seat ECU LH

DTC U1131 - Lost Communication with Rear Climate Control Seat ECU LH

DESCRIPTION

This DTC is output when LIN communication between the rear seat climate control ECU LH and rear power seat module 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 U0211, U0246, U1130 and U1131 are output simultaneously, perform troubleshooting for "Rear Side Switch Module LIN Communication Malfunction" first Rear 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 U1131 is not output.
NG -- CHECK HARNESS OR CONNECTOR (REAR POWER SEAT SWITCH - SEAT CLIMATE CONTROL ECU LH)
OK -- USE SIMULATION METHOD TO CHECK
3. CHECK HARNESS OR CONNECTOR (REAR POWER SEAT SWITCH - SEAT CLIMATE CONTROL ECU LH)




(a) Disconnect the r2*1 or S15*2 module switch connector.
HINT:
*1: except Ottoman
*2: for Ottoman
(b) Disconnect the f28 ECU connector.
(c) Measure the resistance according to the value(s) in the table below.
Standard resistance:

except Ottoman:





for Ottoman:





Standard voltage:

except Ottoman:





for Ottoman:





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

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




(a) Disconnect the f28 ECU connector.
(b) Measure the resistance and voltage according to the value(s) in the table below.
Standard voltage:






Standard voltage:






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

5. REPLACE REAR SEAT CLIMATE CONTROL ECU LH
(a) Temporarily replace the rear seat climate control ECU LH 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 U1131 is not output.
NG -- REPLACE REAR POWER SEAT MODULE SWITCH
OK -- END (REAR SEAT CLIMATE CONTROL ECU LH IS DEFECTIVE)