ENGINE IMMOBILISER SYSTEM(w/ Entry and Start 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 engine 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 engine switch is open or shorted (determined by communication with certification ECU (smart key ECU assembly)) (1 trip detection logic*1):


  • Terminal TXCT or CODE is open (includes disconnection of the engine switch).

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

  • Engine switch

  • Harness or connector

  • Certification ECU (smart key ECU assembly)

 With the shift lever in P*2 or N*3, the electrical key transmitter is held against the engine switch and an engine start operation is performed by pressing and holding the engine switch when the transmitter battery is depleted.

Vehicle Condition and Fail-safe Operation when Malfunction Detected
Vehicle Condition when Malfunction Detected Fail-safe Operation when Malfunction Detected
Engine cannot be started when transmitter battery is depleted by holding electrical key transmitter against engine switch and pressing and holding engine switch with shift lever in P*1 or N*2 -

Related Data List and Active Test
DTC Code Data List and Active Test
B2784 -

WIRING DIAGRAM

A005LHCE01
*a CODE
*b CERTIFICATION ECU (SMART KEY ECU ASSEMBLY)
*c ENGINE SWITCH

CAUTION / NOTICE / HINT

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 engine 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 engine switch grounds or does not ground this signal accordingly.

  • After performing repairs, 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.

    OK

    USE SIMULATION METHOD TO CHECK Click here

    NG

  3. CHECK HARNESS AND CONNECTOR (CERTIFICATION ECU (SMART KEY ECU ASSEMBLY) - ENGINE SWITCH)


    1. Disconnect the F63 certification ECU (smart key ECU assembly) connector.

    2. Disconnect the F59 engine switch connector.

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

      Standard Resistance (Check for Open)
      Tester Connection Condition Specified Condition
      F63-1 (VC5) - F59-10 (VC5) Always Below 1 Ω
      F63-7 (CODE) - F59-8 (CODE) Always Below 1 Ω
      F63-9 (TXCT) - F59-7 (TXCT) Always Below 1 Ω
      F63-24 (AGND) - F59-6 (AGND) Always Below 1 Ω
      Standard Resistance (Check for Short)
      Tester Connection Condition Specified Condition
      F63-1 (VC5) or F59-10 (VC5) - Body ground Always 10 kΩ or higher
      F63-7 (CODE) or F59-8 (CODE) - Body ground Always 10 kΩ or higher
      F63-9 (TXCT) or F59-7 (TXCT) - Body ground Always 10 kΩ or higher

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  4. REPLACE ENGINE SWITCH


    1. Temporarily replace the engine switch with a new or normally functioning one.



    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.

    OK

    END (ENGINE SWITCH WAS DEFECTIVE)

    NG

    REPLACE CERTIFICATION ECU (SMART KEY ECU ASSEMBLY)