ECD SYSTEM (w/o DPF), Diagnostic DTC:P0116

DTC Code DTC Name
P0116 Engine Coolant Temperature Circuit Range / Performance Problem

DESCRIPTION

A thermistor is built into the engine coolant temperature sensor and it changes its resistance value according to the engine coolant temperature.

The structure of the sensor and connection to the ECM is the same as the intake air temperature sensor.

DTC No. DTC Detection Condition Trouble Area
P0116

If the engine coolant temperature was between -40°C (-40°F) and 60°C (140°F) at engine start, and condition (a) and (b) are met:

(2 trip detection logic)

(a) Vehicle is driven at varying speeds (accelerating and decelerating)

(b) Engine coolant temperature remains within 3°C (5.4°F) of the engine starting temperature

  • Thermostat

  • Engine coolant temperature sensor

If the engine coolant temperature was more than 60°C (140°F) at engine start, and conditions (a) and (b) are met:

(6 trip detection logic)

(a) Vehicle is driven at varying speeds (accelerating and decelerating)

(b) Engine coolant temperature remains within 1°C (1.8°F) of the engine starting temperature, and this is successively recorded 6 times

MONITOR DESCRIPTION

The engine coolant temperature sensor is used to monitor the engine coolant temperature. The engine coolant temperature sensor has a thermistor that varies its resistance depending on the temperature of the engine coolant. When the coolant temperature is low, the resistance of the thermistor increases. When the temperature is high, the resistance drops. The variations in resistance are reflected in the voltage output from the sensor. The ECM monitors the sensor voltage and uses this value to calculate the engine coolant temperature. When the sensor's voltage output varies slightly, the ECM interprets this as a fault in the engine coolant temperature sensor and sets a DTC.

Examples:


  1. Upon starting the engine, the engine coolant temperature was between -40°C (-40°F) and 60 °C (140°F). If after driving for a few minutes, the engine coolant temperature still remains within 3°C (5.4°F) of the staring temperature, a DTC will be set. (2 trip detection logic)

  2. Upon starting the engine, the engine coolant temperature was over 60°C (140°F). If after driving for a few minutes, the engine coolant temperature still remains within 1°C (1.8°F) of the starting temperature, a DTC will be set. (6 trip detection logic)

INSPECTION PROCEDURE

Tech Tips


  • If DTCs P0115, P0116, P0117, and P0118 are output simultaneously, the engine coolant temperature sensor circuit may have an open or short. Perform troubleshooting for those DTCs first.

  • Read freeze frame data using an intelligent tester. Freeze frame data record the engine condition when malfunctions are detected. When troubleshooting, freeze frame data can help determine if the vehicle was moving or stationary, if the engine was warmed up or not, if the air-fuel ratio was lean or rich, and other data, from the time the malfunction occurred.

PROCEDURE


  1. CHECK OTHER DTC OUTPUT (IN ADDITION TO DTC P0116)


    1. Connect an intelligent tester to the DLC3.

    2. Turn the ignition switch to ON.

    3. Turn the tester ON.

    4. Select the following menu items: Powertrain / Engine / DTC.

    5. Read DTCs.

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

      Tech Tips

      If any DTCs other than P0116 are output, troubleshoot those DTCs first.


    B

    GO TO DTC CHART

    A

  2. INSPECT THERMOSTAT


    1. Remove the thermostat Click here.

    2. Check the valve opening temperature of the thermostat.

      Standard
      80 to 84°C (176 to 183°F)

      Tech Tips

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

    3. Reinstall the thermostat Click here.


    NG

    REPLACE THERMOSTAT

    OK

    REPLACE ENGINE COOLANT TEMPERATURE SENSOR