SFI SYSTEM, Diagnostic DTC:P0197, P0198

DTC Code DTC Name
P0197 Engine Oil Temperature Sensor Low
P0198 Engine Oil Temperature Sensor High

DESCRIPTION

A thermistor, whose resistance changes in accordance with the engine oil temperature, is built into the engine oil temperature sensor. As the engine oil temperature decreases, the thermistor resistance increases and as the engine oil temperature increases, the thermistor resistance decreases. The engine oil temperature sensor is connected to the ECM. A voltage of 5 V is supplied from terminal THEO via resistor R of the ECM. Since resistor R and the engine oil temperature sensor are connected in series, both the resistance and the electrical potential of THEO are subject to change in accordance with a change in the engine oil temperature.

DTC No. Detection Item DTC Detection Condition Trouble Area MIL Memory
P0197 Engine Oil Temperature Sensor Low Short in engine oil temperature sensor circuit (1 trip detection logic).

  • Short in engine oil temperature sensor circuit

  • Engine oil temperature sensor

  • ECM

 Comes on DTC stored
P0198 Engine Oil Temperature Sensor High Open in engine oil temperature sensor circuit (1 trip detection logic).

  • Open in engine oil temperature sensor circuit

  • Engine oil temperature sensor

  • ECM

 Comes on DTC stored

MONITOR DESCRIPTION

The ECM monitors the engine oil temperature sensor and uses the sensor voltage to calculate the engine oil temperature. If the output voltage from the sensor deviates from the standard range, the ECM determines that the engine oil temperature sensor has malfunctioned and stores a DTC.

Example:

If the engine oil temperature sensor output voltage is higher than 4.95 V for 3 seconds or more, the ECM determines that the engine oil temperature sensor circuit is open and stores DTC P0198. If the engine oil temperature sensor output voltage is less than 0.05 V for 3 seconds or more, the ECM determines that the engine oil temperature sensor circuit is shorted and stores DTC P0197.

MONITOR STRATEGY

Frequency of Operation Continuous

CONFIRMATION DRIVING PATTERN


  1. Connect the GTS to the DLC3.

  2. Turn the engine switch on (IG) and turn the GTS on.

  3. Clear the DTCs (even if no DTCs are stored, perform the clear DTC procedure).

  4. Turn the engine switch off and wait for at least 30 seconds.

  5. Turn the engine switch on (IG) and turn the GTS on.

  6. Wait 10 seconds or more.

  7. Enter the following menus: Powertrain / Engine and ECT / Trouble Codes.

  8. Read the pending DTCs.

    Tech Tips


    • If a pending DTC is output, the system is malfunctioning.

    • If a pending DTC is not output, perform the following procedure.

  9. Enter the following menus: Powertrain / Engine and ECT / Utility / All Readiness.

  10. Input the DTC: P0197 or P0198.

  11. Check the DTC judgment result.

    GTS Display Description
    NORMAL

    • DTC judgment completed

    • System normal
    ABNORMAL

    • DTC judgment completed

    • System abnormal
    INCOMPLETE

    • DTC judgment not completed

    • Perform driving pattern after confirming DTC enabling conditions
    N/A

    • Unable to perform DTC judgment

    • Number of DTCs which do not fulfill DTC preconditions has reached ECU memory limit

    Tech Tips


    • If the judgment result shows NORMAL, the system is normal.

    • If the judgment result shows ABNORMAL, the system has a malfunction.

    • If the judgment result shows INCOMPLETE or N/A, perform the Confirmation Driving Pattern and check the DTC judgment result again.

WIRING DIAGRAM

B008JICE02
*a THEO
*b ETHE
*c Engine Oil Temperature Sensor

CAUTION / NOTICE / HINT

Tech Tips

Read freeze frame data using the GTS. The ECM records vehicle and driving condition information as freeze frame data the moment a DTC is stored. 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 GTS (ENGINE OIL TEMPERATURE SENSOR)


    1. Connect the GTS to the DLC3.

    2. Start the engine and warm it up.

    3. Turn the GTS on.

    4. Enter the following menus: Powertrain / Engine and ECT / Data List / All Data / Engine Oil Temperature Sensor.


      Powertrain > Engine and ECT > Data List
      Tester Display
      Engine Oil Temperature Sensor

    5. Read the value displayed on the GTS.

      Standard Value
      Between 80 and 110°C (176 and 230°F) with warm engine and engine idling
      Result
      Result Proceed to
      -40°C (-40°F) A
      Higher than 180°C (356°F) B
      Between 80 and 110°C (176 and 230°F) C

      Tech Tips


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

      • If there is a short circuit, the GTS indicates higher than 180°C (356°F).


    B

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

    C

    CHECK FOR INTERMITTENT PROBLEMS Click here

    A

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


    1. B008HNKC06
      *1 Engine Oil Temperature Sensor
      *2 ECM
      *a

      Front view of wire harness connector

      (to Engine Oil Temperature Sensor)

      Disconnect the engine oil temperature sensor connector.

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

    3. Connect the GTS to the DLC3.

    4. Turn the engine switch on (IG).

    5. Turn the GTS on.

    6. Enter the following menus: Powertrain / Engine and ECT / Data List / All Data / Engine Oil Temperature Sensor.


      Powertrain > Engine and ECT > Data List
      Tester Display
      Engine Oil Temperature Sensor

    7. Read the value displayed on the GTS.

      Standard Value
      Higher than 180°C (356°F)
      Result
      Proceed to
      OK
      NG

    OK

    REPLACE ENGINE OIL TEMPERATURE SENSOR Click here

    NG

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


    1. Disconnect the engine oil 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
      C61-2 - C65-89 (THEO) Always Below 1 Ω
      C61-1 - C65-90 (ETHE) Always Below 1 Ω
      Result
      Proceed to
      OK
      NG

    OK

    REPLACE ECM Click here

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

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


    1. B008I27C19
      *1 Engine Oil Temperature Sensor
      *2 ECM

      Disconnect the engine oil temperature sensor connector.

    2. Connect the GTS to the DLC3.

    3. Turn the engine switch on (IG).

    4. Turn the GTS on.

    5. Enter the following menus: Powertrain / Engine and ECT / Data List / All Data / Engine Oil Temperature Sensor.


      Powertrain > Engine and ECT > Data List
      Tester Display
      Engine Oil Temperature Sensor

    6. Read the value displayed on the GTS.

      Standard Value
      -40°C (-40°F)
      Result
      Proceed to
      OK
      NG

    OK

    REPLACE ENGINE OIL TEMPERATURE SENSOR Click here

    NG

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


    1. Disconnect the engine oil 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
      C61-2 or C65-89 (THEO) - Body ground and other terminals Always 10 kΩ or higher
      Result
      Proceed to
      OK
      NG

    OK

    REPLACE ECM Click here

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR