P CODES (POWERTRAIN) P0100 - P0199 P0198

    Definition of Trouble Code P0198: Engine Oil Temperature Sensor High

    The trouble code P0198 is associated with the Engine Oil Temperature (EOT) sensor. The EOT sensor monitors the temperature of the engine oil to help control various engine functions. The P0198 code is triggered when the EOT sensor circuit sends a high voltage signal to the engine control module (ECM). This may be caused by an incorrect sensor reading, a shorted sensor, or damaged wiring.

    How to Diagnose Trouble Code P0198

    Diagnosing the P0198 trouble code involves inspecting the EOT sensor, its wiring, and the engine control module. Follow these steps:

    1. Inspect the EOT sensor: Locate the EOT sensor, which is typically found near the oil filter. Look for signs of damage or corrosion on the sensor or its connector. If the sensor appears damaged, it may need to be replaced.
    2. Check the wiring and connector: Inspect the wiring and connector leading to the EOT sensor. Look for signs of damage, fraying, or loose connections. Repair or replace any damaged wiring or connectors as necessary.
    3. Test the EOT sensor: To test the EOT sensor, disconnect it from the wiring harness and measure its resistance using a digital multimeter. Compare the resistance reading to the manufacturer's specifications. If the resistance is outside the specified range, replace the sensor.
    4. Check the voltage signal: Reconnect the EOT sensor and turn the ignition to the ON position without starting the engine. Use a digital multimeter to measure the voltage signal at the sensor connector. The voltage should be within the manufacturer's specified range. If the voltage is too high, the issue may lie in the ECM or a short in the wiring.
    5. Inspect the ECM: If all the previous steps have been completed and the issue persists, the problem may lie in the engine control module. Inspect the ECM for any signs of damage or loose connections. If necessary, consult a professional technician for further diagnostics and potential replacement of the ECM.

    How to Repair Trouble Code P0198

    Once the problem causing the P0198 trouble code has been diagnosed, follow these steps to repair the issue:

    1. Replace the EOT sensor: If the EOT sensor is faulty, replace it with a new one according to the manufacturer's guidelines.
    2. Repair or replace damaged wiring: If any damaged or frayed wiring is found, repair or replace it as needed.
    3. Replace the ECM: If the engine control module is found to be faulty, replace it with a new one. This should be done by a professional technician to ensure proper programming and installation.


    Trouble code P0198 indicates an issue with the engine oil temperature sensor circuit sending a high voltage signal to the engine control module. To resolve this issue, it is important to diagnose the problem accurately and perform the necessary repairs. By following the steps outlined above, you can effectively address the P0198 code and restore your vehicle to optimal performance.

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