SFI SYSTEM, Diagnostic DTC:P0115, P0117, P0118

DTC Code DTC Name
P0115 Engine Coolant Temperature Circuit
P0117 Engine Coolant Temperature Circuit Low Input
P0118 Engine Coolant Temperature Circuit High Input

DESCRIPTION

A thermistor, whose resistance value varies according to the engine coolant temperature, is built into the engine coolant temperature sensor.

The structure of the sensor and its connection to the ECM are the same as those of the intake air temperature sensor.

Tech Tips

When DTC P0115, P0117 or P0118 is stored, the ECM enters fail-safe mode. During fail-safe mode, the engine coolant temperature is estimated to be 80°C (176°F) by the ECM. The ECM continues operating fail-safe mode until a pass condition is detected.

DTC No. DTC Detection Condition Trouble Area
P0115 An open or short in the engine coolant temperature sensor circuit for 0.5 seconds (1 trip detection logic).

  • Open or short in engine coolant temperature sensor circuit

  • Engine coolant temperature sensor

  • ECM
P0117 A short in the engine coolant temperature sensor circuit for 0.5 seconds (1 trip detection logic).

  • Short in engine coolant temperature sensor

  • Engine coolant temperature sensor

  • ECM
P0118 An open in the engine coolant temperature sensor circuit for 0.5 seconds (1 trip detection logic).

  • Open in engine coolant temperature sensor circuit

  • Engine coolant temperature sensor

  • ECM

Tech Tips

When any of these DTCs are output, check the ECT by entering the following menus: Powertrain / Engine and ECT / Data List / Coolant Temp.

Tester Display Malfunction
-40°C (-40°F) Open circuit
140°C (284°F) or higher Short circuit

MONITOR DESCRIPTION

The engine coolant temperature sensor is used to monitor the engine coolant temperature. The engine coolant temperature sensor has a thermistor with a resistance that varies according to the temperature of the engine coolant. When the coolant temperature is low, the resistance in the thermistor increases. When the temperature is high, the resistance drops. These variations in resistance are reflected in the output voltage from the sensor. The ECM monitors the sensor voltage and uses this value to calculate the engine coolant temperature. When the sensor output voltage deviates from the normal operating range, the ECM interprets this as a fault in the engine coolant temperature sensor and stores a DTC.

Example:

If the sensor output voltage is higher than 4.91 V for 0.5 seconds or more, the ECM determines that there is an open circuit in the engine coolant temperature sensor circuit and stores DTC P0118. Conversely, if the voltage output is below 0.14 V for 0.5 seconds or more, the ECM determines that there is a short in the sensor circuit and stores DTC P0117.

If the malfunction is not repaired successfully, a DTC is stored 0.5 seconds after the engine is next started.

WIRING DIAGRAM

A01DSSEE04

INSPECTION PROCEDURE

Tech Tips

Read freeze frame data using the intelligent tester. Freeze frame data records 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. READ VALUE USING INTELLIGENT TESTER (ENGINE COOLANT TEMPERATURE)


    1. Connect the intelligent tester to the DLC3.

    2. Turn the ignition switch to ON.

    3. Turn the tester on.

    4. Enter the following menus: Powertrain / Engine and ECT / Data List / Coolant Temp.

    5. Read the value displayed on the tester.

      Result
      Result Proceed to
      -40°C (-40°F) A
      140°C (284°F) or higher B
      Between 80°C and 100°C (176°F and 212°F) with warm engine C

      Tech Tips


      • If there is an open circuit, the intelligent tester indicates -40°C (-40°F).


      • If there is a short circuit, the intelligent tester indicates 140°C (284°F) or higher.


    B

    READ VALUE USING INTELLIGENT TESTER (CHECK FOR SHORT IN WIRE HARNESS) Click here

    C

    CHECK FOR INTERMITTENT PROBLEMS Click here

    A

  2. READ VALUE USING INTELLIGENT TESTER (CHECK FOR OPEN IN WIRE HARNESS)

    A01DTEXE07
    Text in Illustration
    *1 Engine Coolant Temperature Sensor
    *2 ECM
    *a

    Front view of wire harness connector

    (to Engine Coolant Temperature Sensor)

    1. Disconnect the engine coolant temperature sensor connector.

    2. Connect terminals 1 and 2 of the engine coolant temperature sensor connector on the wire harness side.

    3. Connect the intelligent tester to the DLC3.

    4. Turn the ignition switch to ON.

    5. Turn the tester on.

    6. Enter the following menus: Powertrain / Engine and ECT / Data List / Coolant Temp.

    7. Read the value displayed on the tester.

      Standard value
      140°C (284°F) or higher.

    8. Reconnect the engine coolant temperature sensor connector.


    NG

    CHECK HARNESS AND CONNECTOR (ENGINE COOLANT TEMPERATURE SENSOR - ECM) Click here

    OK

    CONFIRM GOOD CONNECTION TO SENSOR. IF OK, REPLACE ENGINE COOLANT TEMPERATURE SENSOR Click here

  3. CHECK HARNESS AND CONNECTOR (ENGINE COOLANT TEMPERATURE SENSOR - ECM)


    1. Disconnect the engine coolant temperature sensor connector.

    2. Disconnect the ECM connector.

    3. Measure the resistance according to the value(s) in the table below.

      Standard Resistance
      Tester Connection Condition Specified Condition
      C24-2 - C36-17 (THW) Always Below 1 Ω
      C24-1 - C35-8 (ETHW) Always Below 1 Ω

    4. Reconnect the engine coolant temperature sensor connector.

    5. Reconnect the ECM connector.


    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

    CONFIRM GOOD CONNECTION TO ECM. IF OK, REPLACE ECM Click here

  4. READ VALUE USING INTELLIGENT TESTER (CHECK FOR SHORT IN WIRE HARNESS)

    A01DQ92E06
    Text in Illustration
    *1 Engine Coolant Temperature Sensor
    *2 ECM

    1. Disconnect the engine coolant temperature sensor connector.

    2. Connect the intelligent tester to the DLC3.

    3. Turn the ignition switch to ON.

    4. Turn the tester on.

    5. Enter the following menus: Powertrain / Engine and ECT / Data List / Coolant Temp.

    6. Read the value displayed on the tester.

      Standard value
      -40°C (-40°F)

    7. Reconnect the engine coolant temperature sensor connector.


    NG

    CHECK HARNESS AND CONNECTOR (ENGINE COOLANT TEMPERATURE SENSOR - ECM) Click here

    OK

    REPLACE ENGINE COOLANT TEMPERATURE SENSOR Click here

  5. CHECK HARNESS AND CONNECTOR (ENGINE COOLANT TEMPERATURE SENSOR - ECM)


    1. Disconnect the engine coolant temperature sensor connector.

    2. Disconnect the ECM connector.

    3. Measure the resistance according to the value(s) in the table below.

      Standard Resistance
      Tester Connection Condition Specified Condition
      C24-2 or C36-17 (THW) - Body ground Always 10 kΩ or higher

    4. Reconnect the engine coolant temperature sensor connector.

    5. Reconnect the ECM connector.


    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

    REPLACE ECM Click here