2010 Toyota Yaris 4D Sedan, AutomaticFACTORY OEM SERVICE PROCEDURE

DTC P0116: Engine Coolant Temperature Circuit Range / Performance Problem: Procedure

  1. CHECK ANY OTHER DTCS OUTPUT (IN ADDITION TO DTC P0116) 
    1. Connect a Techstream to the DLC3.
    2. Turn the ignition switch to ON.
    3. Turn the Techstream on.
    4. Enter the following menus: Powertrain / Engine and ECT / Trouble Codes.
    5. Read DTCs.

      Result

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

    B → See step   3 

    A: Go to next step 

  2. INSPECT THERMOSTAT 
    1. Remove the thermostat. Refer to REMOVAL .
    2. Check the valve opening temperature of the thermostat.

      Standard

      80°C to 84°C (176°F 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. Refer to INSTALLATION .

    NG → See step   4 

    OK → See step   5 

  3. GO TO DTC CHART. Refer to  DIAGNOSTIC TROUBLE CODE CHART 
  4. REPLACE THERMOSTAT. Refer to  REMOVAL 
  5. REPLACE ENGINE COOLANT TEMPERATURE SENSOR. Refer to  REMOVAL 
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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