Mike's Workshop Manuals: Service manuals for every vehicle
Home >> Lexus >> 2006 >> LS 430 >> Repair and Diagnosis >> Body & Frame >> Door Locks >> Engine Immobilizer System (W/ Smart Key System) - Diagnostics >> DTC B2780: Push Switch/Key Unlock Warning Switch Malfunction >> Inspection Procedure

Inspection Procedure

  1. READ DATA LIST USING HAND-HELD TESTER 
    1. Connect the hand-held tester to the CAN VIM. Then connect the CAN VIM to the DLC3.
    2. Turn the ignition switch ON with the key that cannot start the engine.
    3. Read the DATA LIST.

    Steering lock ECU: 

    DATA LIST - STEERING LOCK ECU

    Item Measurement Item/ Display (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. 

    NG: Go to step 2 

    OK: REPLACE STEERING LOCK ECU 

  2. INSPECT UNLOCK WARNING SWITCH ASSY 
    1. Remove the unlock warning switch.
    2. Measure the resistance of the switch.

    Standard: 

    UNLOCK WARNING SWITCH - RESISTANCE TABLE

    Tester Connection Switch Position Specified Condition
    3 - 4 Ignition switch pushed Below 1 Ω
    3 - 4 Ignition switch not pushed 10 kΩ or higher
    2 - 4 Key inserted in ignition key cylinder Below 1 Ω
    2 - 4 No key in ignition key cylinder 10 kΩ or higher
    Fig 1: Inspecting Unlock Warning Switch Assy
    G03003076Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

    NG: REPLACE UNLOCK WARNING SWITCH ASSY 

    OK: Go to next step 

  3. CHECK WIRE HARNESS (UNLOCK WARNING SWITCH ASSY - BODY GROUND) 
    1. Disconnect the U7 switch connector.
    2. Measure the resistance of the wire harness side connector.

    Standard: 

    UNLOCK WARNING SWITCH ASSY - BODY GROUND - RESISTANCE TABLE

    Tester connection Specified condition
    U7-4 - Body ground Below 1 Ω
    Fig 2: Checking Wire Harness (Unlock Warning Switch Assy - Body Ground)
    G03003077Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

    NG: REPAIR OR REPLACE HARNESS AND CONNECTOR 

    OK: Go to next step 

  4. CHECK WIRE HARNESS (STEERING LOCK ECU - UNLOCK WARNING SWITCH ASSY) 
    1. Disconnect the S46 ECU connector.
    2. Disconnect the U7 switch connector.
    3. Measure the resistance of the wire harness side connectors.

    Standard: 

    STEERING LOCK ECU - UNLOCK WARNING SWITCH - RESISTANCE TABLE

    Tester connection Specified condition
    S46-12 (KSW) - U7-2 Below 1 Ω
    S46-11 (PUSH) - U7-3 Below 1 Ω
    Fig 3: Checking Wire Harness (Steering Lock ECU - Unlock Warning Switch Assy)
    G03003078Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

    NG: REPAIR OR REPLACE HARNESS AND CONNECTOR 

    OK: REPLACE STEERING LOCK ECU