P0198 2012 Ford Fusion Code - Engine Oil Temperature Sensor Circuit High Input

P0198 indicates that the Engine Control Module (ECM) has detected a high voltage signal from the Engine Oil Temperature (EOT) sensor circuit, suggesting the sensor is reading an unusually high oil temperature.

Symptoms may include the check engine light turning on, reduced engine performance, poor fuel economy, or the engine going into limp mode.

The code can be caused by a faulty EOT sensor, damaged wiring or connectors in the sensor circuit, a short to voltage, or a malfunctioning ECM.

Driving with this code is not recommended, as it can lead to inaccurate oil temperature readings, potential engine overheating, or further damage if the issue is not addressed.

Start by inspecting the EOT sensor and its wiring for visible damage. Use a multimeter to check for proper voltage and resistance, and verify the sensor's signal with a scan tool.

Repairs may include replacing the EOT sensor, repairing damaged wiring or connectors, addressing short circuits, or reprogramming or replacing the ECM if necessary.

Repair costs vary depending on the issue. Replacing the EOT sensor typically costs $100-$200, while wiring repairs or ECM replacement can be more expensive.

While unlikely, severely low or contaminated oil can lead to abnormal temperature readings, so it’s important to check and address the oil condition as part of the diagnosis.

You’ll need a scan tool, multimeter, and possibly wiring diagrams to diagnose the issue accurately.

Clearing the code without fixing the underlying issue will only temporarily turn off the check engine light; the code will likely return.