B1278

MULTIPLEX COMMUNICATION: MULTIPLEX COMMUNICATION SYSTEM: B1278: Combination Switch ECU Communication Stop

DTC B1278 - Combination Switch ECU Communication Stop

DESCRIPTION

This DTC is detected when communication between the combination switch (windshield wiper switch) and network gateway ECU stops for more than 10 seconds.






WIRING DIAGRAM





INSPECTION PROCEDURE

PROCEDURE

1. CHECK OPERATION
(a) Check that the windshield wiper switch can operate the wipers.
OK:
Windshield wiper switch can operate wipers normally.
NG -- CHECK WIRE HARNESS (COMBINATION SWITCH ASSEMBLY (WINDSHIELD WIPER SWITCH) - BATTERY AND BODY GROUND)
OK -- REPLACE WINDSHIELD WIPER SWITCH ASSEMBLY
2. CHECK WIRE HARNESS (COMBINATION SWITCH ASSEMBLY (WINDSHIELD WIPER SWITCH) - BATTERY AND BODY GROUND)




(a) Disconnect the K22 combination switch connector.
(b) Measure the resistance and voltage of the wire harness side connector.
Standard Resistance:






Standard Voltage:






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

3. CHECK RESISTANCE OF COMMUNICATION LINE




(a) Disconnect the K22 switch connector.
(b) Disconnect the K68 and 2F ECU connectors.
(c) Measure the resistance of the wire harness side connectors.
Standard resistance:






Result:






C -- REPAIR OR REPLACE HARNESS AND CONNECTOR
B -- REPLACE WINDSHIELD WIPER SWITCH ASSEMBLY AND WIRE HARNESS CONNECTOR
A -- REPLACE COMBINATION SWITCH ASSEMBLY (WINDSHIELD WIPER SWITCH ASSEMBLY)