B1278

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

DESCRIPTION

This DTC is stored if communication between the windshield wiper switch assembly and gateway ECU stops for more than 10 seconds.





WIRING DIAGRAM





INSPECTION PROCEDURE

NOTICE:
Inspect the fuses for circuits related to this system before performing the following inspection procedure.

HINT
If DTC B1214 or B1215 (+B or GND short malfunction of communication bus) is stored at the same time as DTC B1278, perform troubleshooting for DTC B1214 or B1215 first.

PROCEDURE

1. CHECK HARNESS AND CONNECTOR (WINDSHIELD WIPER SWITCH ASSEMBLY - BATTERY AND BODY GROUND)

(a) Disconnect the J26 connector.





(b) Measure the voltage and resistance according to the value(s) in the table below.

Standard Voltage:





Standard Resistance:





Text in Illustration





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

2. CHECK HARNESS AND CONNECTOR (COMMUNICATION LINE)

(a) Disconnect the J76 and J55 connectors.





(b) Measure the resistance according to the value(s) in the table below.

Standard Resistance:





Text in Illustration





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

3. REPLACE WINDSHIELD WIPER SWITCH ASSEMBLY

(a) Replace the windshield wiper switch assembly Removal.

NEXT -- Continue to next step.

4. CHECK DTC OUTPUT

(a) Clear the DTC Multiplex Communication System.

(b) Recheck for DTCs.

OK:

DTC B1278 is not output.

NG -- REPLACE GATEWAY ECU Removal

OK -- END (WINDSHIELD WIPER SWITCH ASSEMBLY WAS DEFECTIVE)