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.
OK -- REPLACE COMBINATION SWITCH (WINDSHIELD WIPER SWITCH)
NG -- Continue to next step.
2. CHECK WIRE HARNESS (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 OR CONNECTOR
OK -- Continue to next step.
3. CHECK RESISTANCE OF COMMUNICATION LINE





(a) Disconnect the K22 switch connector.
(b) Disconnect the K68 ECU connector.
(c) Disconnect the 1X junction block connector.
(d) Measure the resistance of the wire harness side connectors.
Standard resistance:






Result





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