DTC B278C: Lost Communication with Power Source Control: Procedure

1. Disconnect the L135 and L136 power management control ECU connectors.
2. Measure the resistance and voltage according to the value(s) in the table below.

   Standard Resistance

   Tester Connection	Condition	Specified Condition
   L135-6 (E1) - Body ground	Always	Below 1 Ω

   Standard Voltage

   Tester Connection	Condition	Specified Condition
   L135-1 (AM22) - Body ground	Power switch off	11 to 14 V
   L136-7 (AM21) - Body ground	Power switch off	11 to 14 V

NG → REPAIR OR REPLACE HARNESS OR CONNECTOR 

OK: Go to next step 

1. Disconnect the L62 certification ECU (smart key ECU assembly) connector.
2. Measure the resistance according to the value(s) in the table below.

   Standard Resistance

   Tester Connection	Condition	Specified Condition
   L62-29 (LIN) - L136-11 (LIN2)	Always	Below 1 Ω
   L62-29 (LIN) - Body ground	Always	10 kΩ or higher

NG → REPAIR OR REPLACE HARNESS OR CONNECTOR 

OK: Go to next step 

1. Replace the power management control ECU. Refer to REMOVAL .

NEXT: Go to next step 

1. Clear the DTC. Refer to DTC CHECK / CLEAR .
2. Recheck for DTCs.

   OK

   DTC B278C is not output.

NG → See step   5 

OK → END (POWER MANAGEMENT CONTROL ECU WAS DEFECTIVE)