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ENGINE IMMOBILISER SYSTEM (w/o Smart Entry and Start System), Diagnostic DTC:B2780

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DTC Code DTC Name
B2780 Push Switch / Key Unlock Warning Switch Malfunction
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DESCRIPTION

This DTC will be output if the transponder key ECU assembly does not detect that the unlock warning switch is on even when the ignition switch is in the ON position. Under normal conditions, the unlock warning switch is on when the ignition switch is in the ON position.

DTC No. DTC Detection Condition Trouble Area
B2780 "Unlock warning switch ON" is not detected when ignition switch is ON

  • Wire harness or connector

  • Unlock warning switch assembly

  • Transponder key ECU assembly
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WIRING DIAGRAM

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INSPECTION PROCEDURE

Note:

If the transponder key ECU is replaced, register the key and ECU communication ID.

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PROCEDURE


  1. Click here

    READ VALUE ON INTELLIGENT TESTER (UNLOCK WARNING SWITCH)


    1. Connect the intelligent tester to the DLC3.

    2. Turn the ignition switch to the ON position.

    3. Turn the tester on.

    4. Select Key SW in the Data List and read the tester display.

      Table 1. Immobiliser (Transponder Key ECU):
      Tester Display Measurement Item/Range Normal Condition Diagnostic Note
      Key SW Unlock warning switch signal/ON or OFF

      ON: Key is in ignition key cylinder

      OFF: No key is in ignition key cylinder

      		 -
      OK
      ON (Key is in ignition key cylinder) appears on the screen.

  2. Click here

    INSPECT UNLOCK WARNING SWITCH ASSEMBLY


    1. A017BCWE01

      Remove the unlock warning switch assembly (Click here).

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

      Standard resistance
      Tester Connection Switch Position Specified Condition
      1 - 2

      Switch pushed

      (Key inserted)

      		 Below 1 Ω
      1 - 2

      Switch free

      (Key removed)

      		 10 kΩ or higher

  3. Click here

    CHECK HARNESS AND CONNECTOR (UNLOCK WARNING SWITCH - BODY GROUND)


    1. A017EOLE06

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

      Standard resistance
      Tester Connection Condition Specified Condition
      D16-2 - Body ground Always Below 1 Ω

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    CHECK HARNESS AND CONNECTOR (TRANSPONDER KEY ECU - UNLOCK WARNING SWITCH)


    1. A017G6ZE04

      Disconnect the transponder key ECU connector.

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

      Standard resistance
      Tester Connection Condition Specified Condition
      D37-3 (KSW) - D16-1 Always Below 1 Ω
      D16-1 - Body ground Always 10 kΩ or higher

  5. Click here

    REPLACE TRANSPONDER KEY ECU ASSEMBLY

  6. Click here

    REPLACE UNLOCK WARNING SWITCH ASSEMBLYClick here

  7. Click here

    REPAIR OR REPLACE HARNESS OR CONNECTOR