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 No. Detection Item DTC Detection Condition Trouble Area Note
B2784 Antenna Coil Open / Short

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

  • Terminal AGND, VC5, 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)

DTC Output Confirmation Operation:

With the shift lever in P (except Manual Transaxle), the key is held near the engine switch and an engine start operation is performed by pressing and holding the engine switch when the key battery is depleted.

*: Only output while a malfunction is present.

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 key battery is depleted by holding key near engine switch and pressing and holding engine switch with shift lever in P (except Manual Transaxle) -
Related Data List and Active Test
DTC No. Data List and Active Test
B2784 -

WIRING DIAGRAM

A01QTN5E17
*a CODE
*b Engine Switch
*c Certification ECU (Smart Key ECU Assembly)

CAUTION / NOTICE / HINT

Note


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

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

PROCEDURE


  1. CHECK HARNESS AND CONNECTOR (CERTIFICATION ECU [SMART KEY ECU ASSEMBLY] - ENGINE SWITCH)


    1. Disconnect the G84 certification ECU (smart key ECU assembly) connector.

    2. Disconnect the G24 engine switch connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      G84-7 (CODE) - G24-8 (CODE) Always Below 1 Ω
      G84-9 (TXCT) - G24-7 (TXCT) Always Below 1 Ω
      G84-1 (VC5) - G24-10 (VC5) Always Below 1 Ω
      G84-24 (AGND) - G24-6 (AGND) Always Below 1 Ω
      G84-7 (CODE) - Body ground Always 10 kΩ or higher
      G24-8 (CODE) - Body ground Always 10 kΩ or higher
      G84-9 (TXCT) - Body ground Always 10 kΩ or higher
      G24-7 (TXCT) - Body ground Always 10 kΩ or higher
      G84-1 (VC5) - Body ground Always 10 kΩ or higher
      G24-10 (VC5) - Body ground Always 10 kΩ or higher
      G84-24 (AGND) - Body ground Always 10 kΩ or higher
      G24-6 (AGND) - Body ground Always 10 kΩ or higher
      Result
      Proceed to
      OK
      NG

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  2. REPLACE ENGINE SWITCH


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


      Result
      Proceed to
      NEXT

    NEXT

  3. CLEAR DTC


    1. Clear the DTCs.

      Click here


      Body Electrical > Entry&Start > Clear DTCs
      Result
      Proceed to
      NEXT

    NEXT

  4. CHECK FOR DTC


    1. Check for DTCs.

      Click here

      Tech Tips

      Before checking for DTCs, perform the "DTC Output Confirmation Operation" procedure.


      Body Electrical > Entry&Start > Trouble Codes
      Result
      Proceed to
      DTC B2784 is not output
      DTC B2784 is output

    DTC B2784 is not output

    END (ENGINE SWITCH WAS DEFECTIVE)

    DTC B2784 is output

    REPLACE CERTIFICATION ECU (SMART KEY ECU ASSEMBLY)