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.

Table 1. 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)

-
Table 2. Related Data List and Active Test

DTC No.

Data List and Active Test

B2784

-

WIRING DIAGRAM

B271004E17

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

      Tip:

      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)