2008 Lexus GX 470FACTORY OEM SERVICE PROCEDURE

Inspection Procedure

  1. CHECK FOR EXHAUST GAS LEAK 
    1. Allow the engine to idle.
    2. Check for an exhaust gas leak around the HO2S.

      OK: No leak from the HO2S. 

    NG: REPAIR LEAK 

    OK: Go to Next Step 

  2. CHECK HEATED OXYGEN SENSOR 
    Fig 1: Fuel-Trim And Rear HO2S Voltage Graph
    G04967990Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    1. Warm up the engine.
    2. Allow the engine to idle.
    3. Select the tester menus: Powertrain/Engine and ECT/Active Test/Control the Injection Volume for A/F Sensor
    4. Check the O2S B1S2 (O2S B2S2) values when the Control the Injection Volume for A/F Sensor is -12.5% (Lean fuel-trim).
    5. Check the O2S B1S2 (O2S B2S2) values when the Control the Injection Volume for A/F Sensor is 25% (Rich fuel-trim).

      Standard 

      STANDARD REFERENCE

      Control the Injection Volume for A/F Sensor O2S B1S2 (O2S B2S2)
      -12.5% Less than 0.2 V
      25% More than 0.8 V

    NG: REPLACE HEATED OXYGEN SENSOR 

    OK: Go to Next Step 

  3. CHECK DTC 
    1. Clear DTC.
    2. Turn the ignition switch OFF.
    3. Disconnect the cable from the negative battery terminal and wait for 1 minute.
    4. Connect the cable to the negative battery terminal.
    5. Start the engine.
      Fig 2: Identifying Drive Pattern
      G04967991Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    6. Perform the drive pattern.
      1. Warm up the engine.
      2. Accelerate the vehicle until 80 km/h (50 mph) and stop the vehicle
      3. Drive the vehicle by 60 to 80 km/h (35 to 50 mph) for 5 minutes or more.
    7. Check DTC.

      OK: P0606 is not present. 

    NG: REPLACE ECM 

    OK: CHECK FOR INTERMITTENT PROBLEMS 

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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