ENGINE IMMOBILISER SYSTEM, Diagnostic DTC:B278A

DTC Code DTC Name
B278A Short to GND in Immobiliser System Power Source Circuit

DESCRIPTION

This DTC is output when the engine switch power source supply line is open or shorted.

DTC Code DTC Detection Condition Trouble Area
B278A Engine switch power source supply line is open or shorted

  • Harness and connector


  • Engine switch


  • Certification ECU

WIRING DIAGRAM

A001FL6E58
*1 Engine Switch
*2 Certification ECU

PROCEDURE


  1. CHECK HARNESS AND CONNECTOR (CERTIFICATION ECU - ENGINE SWITCH)

    A001DUOE03
    *1 Front view of wire harness connector: (to Certification ECU)
    *2 Front view of wire harness connector: (to Engine Switch)

    1. Disconnect the L15 ECU connector.

    2. Disconnect the L36 switch connector.

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

      Standard resistance
      Tester Connection Condition Specified Condition
      L15-30 (VC5) - L36-14 (VC5) Always Below 1 Ω
      L15-40 (AGND) - L36-8 (AGND)
      L15-30 (VC5) or L36-14 (VC5) - Body ground Always 10 kΩ or higher
      L15-40 (AGND) or L36-8 (AGND) - Body ground

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  2. REPLACE ENGINE SWITCH


    1. Temporarily replace the engine switch with a new one.



    NEXT

  3. CHECK FOR DTC


    1. Recheck for DTC Click here.

      OK
      DTC B278A is not output.

    OK

    END (ENGINE SWITCH IS DEFECTIVE)

    NG

    REPLACE CERTIFICATION ECU