LEMON Manuals: Even more car manuals for everyone: 1960-2025
Home >> Lexus >> 2007 >> SC 430 >> Repair and Diagnosis >> Body & Frame >> Door Locks >> Door Lock >> Key Reminder Warning System >> Driver Side Door ECU Power Source Circuit >> Inspection Procedure
April 5, 2026: LEMON Manuals is launched! Read the announcement.

Inspection Procedure

  1. INSPECT FUSE (MPX-B1, AM1, MPX-IG, D DOOR, D/C CUT) 
    1. Remove the MPX-IG and AM1 fuses from the driver side junction block.
    2. Remove the MPX-B1 fuse from the passenger side junction block.
    3. Remove the D DOOR and D/C CUT fuses from the engine room No. 1 relay block.
    4. Measure the resistance of the fuses.

      Standard: Below 1 Ω 

    NG: REPLACE FUSE 

    OK: Go to Next Step 

  2. INSPECT IG1 RELAY 
    Fig 1: Inspecting IG1 Relay
    G05292950Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    1. Remove the IG1 relay from the driver side junction block.
    2. Measure the resistance of the relay.

      Standard resistance 

      TESTER CONNECTION SPECIFIED CONDITION CHART

      Tester Connection Specified Condition
      3-5 10 kΩ or higher
      3-5 Below 1 Ω
      (when battery voltage is applied to terminals 1 and 2)

    NG: REPLACE IG1 RELAY 

    OK: Go to Next Step 

  3. CHECK WIRE HARNESS (ECU - BATTERY AND BODY GROUND) 
    1. Disconnect the D19 ECU connector.
    2. Measure the voltage and resistance of the wire harness side connector.

      Standard voltage 

      TESTER CONNECTION SPECIFIED CONDITION CHART

      Tester Connection Condition Specified Condition
      D19-4 (CPUB) - Body ground Always 10 to 14 V
      D19-6 (BDR) - Body ground Always 10 to 14 V
      D19-5 (SIG) - Body ground Ignition switch ON 10 to 14 V

      Standard resistance 

      TESTER CONNECTION SPECIFIED CONDITION CHART

      Tester Connection Specified Condition
      D19-1 (GND) - Body ground Below 1 Ω
      Fig 2: Identifying D19 ECU Connector Terminals
      G05292951Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

    NG: REPAIR OR REPLACE HARNESS OR CONNECTOR 

    OK: REPLACE MULTIPLEX NETWORK FRONT DOOR ECU LH