ELECTRIC POWER CONTROL SYSTEM, Diagnostic DTC:B1012

DTC Code DTC Name
B1012 Battery Power Supply Back Up Circuit

DESCRIPTION


DTC No. DTC Detection Condition Trouble Area
B1012 When BECU voltage is 8.3 V or less, or 16.7 V or more (BECU circuit malfunction)

  • Main body ECU (network gateway ECU)

  • Instrument panel junction block assembly

  • Harness or connector

WIRING DIAGRAM

A004H2CE06
*a from Battery
*b Instrument Panel Junction Block Assembly
*c Main Body ECU (Network Gateway ECU)

CAUTION / NOTICE / HINT

Note

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

PROCEDURE


  1. CLEAR DTC


    1. Clear the DTCs Click here.


    NEXT

  2. CHECK FOR DTC


    1. Check for DTCs Click here.

      Result
      Result Proceed to
      DTC B1012 is output A
      DTC is not output B

    B

    USE SIMULATION METHOD TO CHECK Click here

    A

  3. CHECK HARNESS AND CONNECTOR (BECU VOLTAGE)


    1. Disconnect the 3A instrument panel junction block assembly connector.

    2. A004HN3E03
      Text in Illustration
      *a

      Front view of wire harness connector

      (to Instrument Panel Junction Block Assembly)

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

      Standard Voltage
      Tester Connection Condition Specified Condition
      3A-27 - Body ground Always 11 to 14 V

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  4. CHECK HARNESS AND CONNECTOR (ECU GROUND)


    1. Disconnect the D6 and A73 main body ECU (network gateway ECU) connector.

    2. Disconnect the 3B instrument panel junction block assembly connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      D6-1 (GND) - Body ground Always Below 1 Ω
      A73-4 (GND) - Body ground Always Below 1 Ω
      3B-18 - Body ground Always Below 1 Ω

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  5. INSPECT INSTRUMENT PANEL JUNCTION BLOCK ASSEMBLY


    1. Remove the instrument panel junction block assembly Click here.

    2. Remove the main body ECU (network gateway ECU) from the instrument panel junction block assembly.

      A004IFIE02
      Text in Illustration
      *a

      Component without harness connected

      (Instrument Panel Junction Block Assembly)

      		 - -

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      3A-27 - MB-1 (BECU) Always Below 1 Ω
      3B-18 - MB-11 (GND) Always Below 1 Ω

    OK

    REPLACE MAIN BODY ECU (NETWORK GATEWAY ECU) Click here

    NG

    REPLACE INSTRUMENT PANEL JUNCTION BLOCK ASSEMBLY Click here