2007 Lexus SC 430FACTORY OEM SERVICE PROCEDURE

Inspection Procedure

  1. DRIVING TEST 

    HINT:

    • The driving test should be done on a paved road (nonskid road).
    • Make sure not to use the TRAC system when testing a vehicle equipped with one.
    1. Start the engine.
    2. Turn the ECT SNOW switch OFF (Normal drive mode).
    3. Confirm vehicle response by driving from a parked position to fully depressing the accelerator pedal.
    4. Turn the ECT SNOW switch ON and perform the same check as above.

      When driving the vehicle with the ECT SNOW switch ON and OFF, check that there is a difference in acceleration.

      OK: There is a difference in acceleration. 

    OK: PROCEED TO NEXT CIRCUIT INSPECTION SHOWN IN PROBLEM SYMPTOMS TABLE 

    NG: Go to Next Step 

  2. CHECK WIRE HARNESS (PATTERN SELECT SWITCH - BODY GROUND) 
    1. Disconnect the E11 switch connector.
      Fig 1: Identifying E11 Wire Harness (Pattern Select Switch - Body Ground) Connector Terminals
      G05289628Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    2. Measure the resistance of the wire harness side connector.

      Standard resistance 

      TESTER CONNECTION SPECIFIED CONDITION

      Tester Connection Specified Condition
      E11-3 - Body ground Below 1 Ω

    NG: REPAIR OR REPLACE HARNESS AND CONNECTOR 

    OK: Go to Next Step 

  3. INSPECT PATTERN SELECT SWITCH 
    1. Measure the resistance of the switch.
      Fig 2: Identifying E3 And 2nd Connector Terminals
      G05289629Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

      Standard resistance 

      TESTER CONNECTION SPECIFIED CONDITION

      Tester Connection Switch Condition Specified Condition
      3 (E) -1 (2ND) Continuously press pattern select switch (SNOW) Below 1 Ω
      3 (E) -1 (2ND) Release pattern select switch (SNOW) 10 kΩ or higher

    NG: REPLACE PATTERN SELECT SWITCH 

    OK: Go to Next Step 

  4. CHECK WIRE HARNESS (PASSENGER SIDE JUNCTION BLOCK ECU - PATTERN SELECT SWITCH) 
    Fig 3: Identifying P4 Passenger Side Junction Block Connector Terminals
    G05289630Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    1. Disconnect the P4 ECU connector.
    2. Measure the resistance of the passenger side junction block ECU.

      Standard resistance 

      TESTER CONNECTION SPECIFIED CONDITION

      Tester Connection Switch Condition Specified Condition
      P4-17 (SNOW) -Body ground Continuously press pattern select switch (SNOW) Below 1 Ω
      P4-17 (SNOW) - Body ground Release pattern select switch (SNOW) 10 kΩ or higher

    NG: REPAIR OR REPLACE HARNESS AND CONNECTOR 

    OK: PROCEED TO NEXT CIRCUIT INSPECTION SHOWN IN PROBLEM SYMPTOMS TABLE 

Factory Service Tools

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When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

  • • You smell fuel, burning insulation, or see smoke.
  • • Brakes feel soft, pull hard to one side, or make grinding noises.
  • • The engine overheats, stalls repeatedly, or misfires under load.
  • • You are missing required tools, torque specs, or safe lifting equipment.
  • • You are not confident in the next step or safety outcome.

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