SFI SYSTEM (w/ Secondary Air Injection 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 is built into the Engine Coolant Temperature (ECT) sensor, of which the resistance value varies according to the ECT.

The structure of the sensor and its connection to the ECM are the same as those of the Intake Air Temperature (IAT) sensor.

Tech Tips

When any of DTCs P0115, P0117 and P0118 are set, the ECM enters fail-safe mode. During fail-safe mode, the ECT is estimated to be 80°C (176°F) by the ECM. Fail-safe mode continues until a pass condition is detected.

DTC No. Proceed To DTC Detection Conditions Trouble Areas
P0115 Step 1

Open or short in Engine Coolant Temperature (ECT) sensor circuit for 0.5 seconds

(1 trip detection logic)

  • Open or short in ECT sensor circuit

  • ECT sensor

  • ECM
P0117 Step 4

Short in Engine Coolant Temperature (ECT) sensor circuit for 0.5 seconds

(1 trip detection logic)

  • Short in ECT sensor circuit

  • ECT sensor

  • ECM
P0118 Step 2

Open in Engine Coolant Temperature (ECT) sensor circuit for 0.5 seconds

(1 trip detection logic)

  • Open in ECT sensor circuit

  • ECT sensor

  • ECM

Tech Tips

When any of these DTCs are set, check the ECT by selecting the following menu items on an intelligent tester: Powertrain / Engine and ECT / Data List / Coolant Temp.

Temperature Displayed Malfunctions
-40°C (-40°F) Open circuit
140°C (284°F) or higher Short circuit

MONITOR DESCRIPTION

The Engine Coolant Temperature (ECT) sensor is used to monitor the ECT. The ECT 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 voltage output from the sensor. The ECM monitors the sensor voltage and uses this value to calculate the ECT. When the sensor output voltage deviates from the normal operating range, the ECM interprets this as a fault in the ECT sensor and sets a DTC.

Example:

If the sensor voltage output is -40°C (-40°F) for 0.5 seconds or more, the ECM determines that there is an open in the ECT sensor circuit, and sets DTC P0118. Conversely, if the voltage output is more than 140°C (284°F) for 0.5 seconds or more, the ECM determines that there is a short in the sensor circuit, and sets DTC P0117.

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

WIRING DIAGRAM

A01BH1LE02

INSPECTION PROCEDURE

Tech Tips


  • If other DTCs relating to different systems that have terminal E2 as the ground terminal are output simultaneously, terminal E2 may have an open circuit.

  • Read freeze frame data using an intelligent tester. 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.

PROCEDURE


  1. READ VALUE USING INTELLIGENT TESTER (ENGINE COOLANT TEMPERATURE)


    1. Connect an intelligent tester to the DLC3.

    2. Turn the ignition switch to the ON position.

    3. Turn the tester ON.

    4. Select the following menu items: Powertrain / Engine and ECT / Data List / Coolant Temp.

    5. Read the value displayed on the tester.

      Standard
      Between 80°C and 97°C (176°F and 207°F) with warm engine.
      Result
      Temperature Displayed Proceed To
      -40°C (-40°F) A
      140°C (284°F) or higher B
      Between 80°C and 97°C (176°F and 207°F) 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 HARNESS) Click here

    C

    CHECK FOR INTERMITTENT PROBLEMS

    A

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


    1. Confirm good connection of the connector to the ECT sensor.

    2. A01BEIHE01

      Disconnect the D32 Engine Coolant Temperature (ECT) sensor connector.

    3. Connect terminals 1 and 2 of the ECT sensor connector on the wire harness side.

    4. Connect the intelligent tester to the DLC3.

    5. Turn the ignition switch to the ON position.

    6. Turn the tester ON.

    7. Select the following menu items: Powertrain / Engine and ECT / Data List / Coolant Temp.

    8. Read the value displayed on the tester.

      Standard
      140°C (284°F) or higher

    9. Reconnect the ECT sensor connector.


    OK

    REPLACE ENGINE COOLANT TEMPERATURE SENSOR

    NG

  3. READ VALUE USING INTELLIGENT TESTER (CHECK FOR OPEN IN ECM)


    1. Confirm good connection of the connectors to the ECM.

    2. A01BAJPE02

      Disconnect the D32 ECT sensor connector.

    3. Connect terminals THW and E2 of the ECM connector.

      Tech Tips

      Before checking, perform visual and contact pressure checks on the ECM connector.

    4. Connect the intelligent tester to the DLC3.

    5. Turn the ignition switch to the ON position.

    6. Turn the tester ON.

    7. Select the following menu items: Powertrain / Engine and ECT / Data List / Coolant Temp.

    8. Read the value displayed on the tester.

      Standard
      140°C (284°F) or higher

    9. Reconnect the ECT sensor connector.


    OK

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    NG

    REPLACE ECM

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


    1. A01BGFRE10

      Disconnect the D32 ECT sensor connector.

    2. Connect the intelligent tester to the DLC3.

    3. Turn the ignition switch to the ON position.

    4. Turn the tester ON.

    5. Select the following menu items: Powertrain / Engine and ECT / Data List / Coolant Temp.

    6. Read the value displayed on the tester.

      Standard
      -40°C (-40°F)

    7. Reconnect the ECT sensor connector.


    OK

    REPLACE ENGINE COOLANT TEMPERATURE SENSOR

    NG

  5. READ VALUE USING INTELLIGENT TESTER (CHECK FOR SHORT IN ECM)


    1. A01BGNDE01

      Disconnect the D1 ECM connector.

    2. Connect the intelligent tester to the DLC3.

    3. Turn the ignition switch to the ON position.

    4. Turn the tester ON.

    5. Select the following menu items: Powertrain / Engine and ECT / Data List / Coolant Temp.

    6. Read the value displayed on the tester.

      Standard
      -40°C (-40°F)

    7. Reconnect the ECT sensor connector.


    OK

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    NG

    REPLACE ECM