MULTIPLEX COMMUNICATION SYSTEM, Diagnostic DTC:B1278

DTC Code DTC Name
B1278 Combination Switch ECU Communication Stop

DESCRIPTION

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

DTC No. DTC Detection Condition Trouble Area
B1278 Windshield wiper switch ECU communication stops

  • Windshield wiper switch assembly

  • Wire harness or connector

WIRING DIAGRAM

A0160BTE04

INSPECTION PROCEDURE

Tech Tips

If "+B of GND short malfunction of communication bus" DTCs (B1214 and B1215) are detected at the same time as "communication stop" DTC B1278, repair the "+B or GND short malfunction of communication bus" DTCs first Click here.

PROCEDURE


  1. INSPECT FUSE (ECU-IG RH, MPX-B)


    1. Remove the ECU-IG RH fuse from the main body ECU RH (cowl side junction block RH).

    2. Remove the MPX-B fuse from the engine room relay block No. 1.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      ECU-IG RH fuse Always Below 1 Ω
      MPX-B fuse Always Below 1 Ω

    NG

    REPLACE FUSE (ECU-IG RH, MPX-B)

    OK

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


    1. A0162R1E11

      Disconnect the J26 connector.

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

      Standard Voltage
      Tester Connection Condition Specified Condition
      J26-1 (B) - Body ground Always 11 to 14 V
      J26-2 (IG) - Body ground Engine switch on (IG) 11 to 14 V
      Standard Resistance
      Tester Connection Condition Specified Condition
      J26-5 (E) - Body ground Always Below 1 Ω

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR (WINDSHIELD WIPER SWITCH ASSEMBLY - BATTERY AND BODY GROUND)

    OK

  3. CHECK HARNESS AND CONNECTOR


    1. A01616IE04

      Disconnect the J26, J76 and J55 connectors.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      J26-6 (MPX1) - J76-12 (MPD2) Always Below 1 Ω
      J26-7 (MPX2) - J55-7 (MPX1) Always Below 1 Ω

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR (COMMUNICATION LINE)

    OK

    REPLACE WINDSHIELD WIPER SWITCH ASSEMBLY Click here