2008 Lexus GX 470FACTORY OEM SERVICE PROCEDURE

Inspection Procedure

HINT:

  • If DTC P0115, P0116, P0117 and P0118 are output simultaneously, the ECT sensor circuit may be open or shorted. Perform the troubleshooting of DTC P0115, P0117 or P0118 first.
  • Read freeze frame data using the Techstream. The ECM records vehicle and driving condition information as freeze frame data the moment a DTC is stored. When troubleshooting, freeze frame data can be helpful in determining whether the vehicle was running or stopped, whether the engine was warmed up or not, whether the air/fuel ratio was lean or rich, as well as other data recorded at the time of a malfunction.
  1. CHECK ANY OTHER DTCS OUTPUT (IN ADDITION TO DTC P0116) 
    1. Connect the Techstream to the DLC3.
    2. Turn the ignition switch ON and turn the tester ON.
    3. Enter the following menus: Powertrain/Engine and ECT/Trouble Codes.
    4. Read the DTCs.

      Result 

      RESULT REFERENCE

      Display (DTC Output) Proceed to
      P0116 A
      P0116 and other DTCs B

    B: GO TO RELEVANT DTC CHART 

    A: Go to next step 

  2. INSPECT THERMOSTAT 
    1. Remove the thermostat (See INSPECTION ).
    2. Check the valve opening temperature of the thermostat (See INSPECTION ).

      Standard opening temperature: 

      80 to 84°C (176 to 183°F) 

      HINT:

      In addition to the above check, confirm that the valve is completely closed when the temperature is below the standard.

    3. Reinstall the thermostat (See INSTALLATION ).

    NG: REPLACE THERMOSTAT 

    OK: REPLACE ENGINE COOLANT TEMPERATURE SENSOR 

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.