DTC B1278: Combination Switch ECU Communication Stop: Procedure

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: Go to next step 

1. Disconnect the J26 connector.
   Fig 1: Identifying J26 Connector Terminal

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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 - BATTERY AND BODY GROUND) 

OK: Go to next step 

1. Disconnect the J26, J76 and J55 connectors.
   Fig 2: Identifying J26, J76 And J55 Connector Terminal

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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 

OK → See step   4