ENGINE IMMOBILISER SYSTEM, Diagnostic DTC:B2780

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

DESCRIPTION

This DTC will be output if the transponder key ECU does not detect that the unlock warning switch is ON even when the key is inserted into the ignition key cylinder. Under normal conditions, the unlock warning switch is ON when the key is inserted into the ignition key cylinder.

DTC No. DTC Detection Condition Trouble Area
B2780 Unlock warning switch ON is not detected when key is inserted into ignition key cylinder

  • Unlock warning switch assembly

  • Wire harness

  • Transponder key ECU

WIRING DIAGRAM

A01J4DIE03

INSPECTION PROCEDURE

PROCEDURE


  1. READ VALUE USING INTELLIGENT TESTER (UNLOCK WARNING SWITCH ASSEMBLY)


    1. Check the Data List for proper functioning of the unlock warning switch.

      Transponder key ECU:
      Item Measurement Item/Display (Range) Normal Condition Diagnostic Note
      Key SW Unlock warning switch signal / ON or OFF

      OFF: No key is in ignition key cylinder

      ON: Key is in ignition key cylinder

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

    OK

    REPLACE TRANSPONDER KEY ECU

    NG

  2. INSPECT UNLOCK WARNING SWITCH ASSEMBLY

    A01J5VNE01

    1. Remove the switch.

    2. Measure the resistance of the switch.

      Standard resistance
      Tester Connection Switch Condition Specified Condition
      1 - 2 Pushed Below 1 Ω
      Not pushed 10 kΩ or higher

    NG

    REPLACE UNLOCK WARNING SWITCH ASSEMBLY

    OK

  3. CHECK WIRE HARNESS (UNLOCK WARNING SWITCH - TRANSPONDER KEY ECU AND BODY GROUND)

    A01J5SPE04

    1. Disconnect the U1 switch connector.

    2. Disconnect the T21 ECU connector.

    3. Measure the resistance of the wire harness side connectors.

      Standard resistance
      Tester Connection Specified Condition
      T21-3 (KSW) - U1-1 Below 1 Ω
      U1-2 - Body ground

    NG

    REPAIR OR REPLACE HARNESS AND CONNECTOR

    OK

    REPLACE TRANSPONDER KEY ECU