B1478

NETWORKING: LIN COMMUNICATION SYSTEM: B1478: Climate Control Seat ECU Communication Error

DTC B1478 - Climate Control Seat ECU Communication Error

DESCRIPTION

This DTC is stored when LIN communication between the air conditioning amplifier and seat climate control ECUs 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.

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 DTCs Reading and Clearing Diagnostic Trouble Codes.

Result





B -- USE SIMULATION METHOD TO CHECK
A -- Continue to next step.
3. CHECK HARNESS AND CONNECTOR (AIR CONDITIONING AMPLIFIER - SEAT CLIMATE CONTROL ECU)




(a) Disconnect the E36 amplifier connector.
(b) Disconnect the c24 and c38 ECU connectors.
(c) Measure the resistance and voltage according to the value(s) in the tables below.
Standard Resistance:






Standard Voltage:






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 c24 and c38 ECU connectors.
(b) Measure the resistance and voltage according to the value(s) in the tables below.
Standard Resistance:






Standard Voltage:






NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR
OK -- Continue to next step.
5. CHECK SEAT CLIMATE CONTROL ECU LH
(a) Temporarily replace the seat climate control ECU LH with a new or normally functioning one Disassembly.
(b) Check that the driver side seat climate control function is normal.
OK:
Driver side seat climate control function is normal.
NG -- CHECK SEAT CLIMATE CONTROL ECU RH
OK -- END (SEAT CLIMATE CONTROL ECU LH IS DEFECTIVE)
6. CHECK SEAT CLIMATE CONTROL ECU RH
(a) Temporarily replace the seat climate control ECU RH with a new or normally functioning one Disassembly.
(b) Check that the driver side seat climate control function is normal.
OK:
Front passenger side seat climate control function is normal.
NG -- REPLACE AIR CONDITIONING AMPLIFIER
OK -- END (SEAT CLIMATE CONTROL ECU RH IS DEFECTIVE)