2007 Lexus SC 430FACTORY OEM SERVICE PROCEDURE

On-Vehicle Inspection

  1. DISCONNECT CABLE FROM NEGATIVE BATTERY TERMINAL 
    CAUTION: Wait at least 90 seconds after disconnecting the cable from the negative (-) battery terminal to prevent airbag and seat belt pretensioner activation.
  2. REMOVE IG1 RELAY 
    1. Remove the IG1 relay from the instrument panel junction block.
  3. INSPECT RELAY 
    Fig 1: Inspecting IG1 Relay
    G05291615Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    1. Measure resistance of the IG1 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)

      If the result is not as specified, replace the relay.

  4. INSTALL IG1 RELAY 
  5. CONNECT CABLE TO NEGATIVE BATTERY TERMINAL 
  6. PERFORM INITIALIZATION 
    1. Perform initialization (see INITIALIZATION ).
      NOTE: Certain systems need to be initialized after disconnecting and reconnecting the cable from the negative (-) battery terminal.
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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