ENGINE IMMOBILISER SYSTEM, Diagnostic DTC:B2784

DTC Code DTC Name
B2784 Antenna Coil Open / Short

DESCRIPTION

When an open or short circuit is detected in the transponder key amplifier coil built into the power switch, the certification ECU (smart key ECU assembly) stores this DTC. This DTC is also stored as a past DTC.

DTC Code DTC Detection Condition Trouble Area DTC Output Confirmation Operation
B2784

The transponder key amplifier coil built into the power switch is open (see below) or shorted (determined by communication with certification ECU (smart key ECU assembly)) (1 trip detection logic*).


  • Terminal VC5, TXCT or CODE is open (includes disconnection of the power switch).

  • The transponder key amplifier coil built into the power switch is open.

  • Power switch

  • Wire harness or connector

  • Certification ECU (smart key ECU assembly)

 With park (P) selected, the key is held against the power switch and a hybrid control system start operation is performed by pressing and holding the power switch when the key battery is depleted.

Vehicle Condition and Fail-safe Operation when Malfunction Detected
Vehicle Condition when Malfunction Detected Fail-safe Operation when Malfunction Detected
Hybrid control system cannot be started when key battery is depleted by holding key against power switch and pressing and holding power switch with park (P) selected -
Related Data List and Active Test
DTC Code Data List and Active Test
B2784 -

WIRING DIAGRAM

A003ZCCE44

INSPECTION PROCEDURE

Note


  • Before replacing the certification ECU (smart key ECU assembly), refer to the Service Bulletin.

  • The certification ECU (smart key ECU assembly) outputs a fixed 5 V power source voltage through a resistance from terminal CODE. The power switch grounds or does not ground this power source voltage accordingly.

  • The certification ECU (smart key ECU assembly) outputs a fixed 5 V power source voltage through a resistance and transistor. The power switch grounds or does not ground this signal accordingly.

  • After performing repair, perform the operation that fulfills the DTC output confirmation operation, and then confirm that no DTCs are output again.

PROCEDURE


  1. CLEAR DTC


    1. Clear the DTCs Click here.


    NEXT

  2. CHECK FOR DTC


    1. Perform the operation that fulfills the DTC output confirmation operation.

    2. Check for DTCs Click here.

      OK
      DTC B2784 is not output.

    NG

    CHECK HARNESS AND CONNECTOR (CERTIFICATION ECU - POWER SWITCH) Click here

    OK

    USE SIMULATION METHOD TO CHECK Click here

  3. CHECK HARNESS AND CONNECTOR (CERTIFICATION ECU - POWER SWITCH)


    1. Disconnect the H1*1 or H143*2 ECU connector.


      • *1: w/ Entry Function

      • *2: w/o Entry Function

    2. Disconnect the H78 switch connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition

      H1-13 (CODE) - H78-10 (CODE)*1

      H143-13 (CODE) - H78-10 (CODE)*2

      		 Always Below 1 Ω

      H1-12 (TXCT) - H78-9 (TXCT)*1

      H143-12 (TXCT) - H78-9 (TXCT)*2

      H1-13 (CODE) or H78-10 (CODE) - Body ground*1

      H143-13 (CODE) or H78-10 (CODE) - Body ground*2

      		 Always 10 kΩ or higher

      H1-12 (TXCT) or H78-9 (TXCT) - Body ground*1

      H143-12 (TXCT) or H78-9 (TXCT) - Body ground*2

      • *1: w/ Entry Function

      • *2: w/o Entry Function


    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  4. REPLACE POWER SWITCH


    1. Temporarily replace the power switch with a new or known good one Click here.


    NEXT

  5. CLEAR DTC


    1. Clear the DTCs Click here.


    NEXT

  6. CHECK FOR DTC


    1. Perform the operation that fulfills the DTC output confirmation operation.

    2. Check for DTCs Click here.

      OK
      DTC B2784 is not output.

    NG

    REPLACE CERTIFICATION ECU (SMART KEY ECU ASSEMBLY)

    OK

    END (POWER SWITCH WAS DEFECTIVE)