P0198 - ENGINE OIL TEMPERATURE SENSOR CIRCUIT HIGH
Description of DTC code P0198
The EOT sensor (Engine Oil Temperature) is a device that sends a voltage signal to the PCM (Powertrain Control Module) to calculate fuel quality and fuel injection timing. This signal also checks the operation of the glow plugs. It has 5-reference volts provided by the PCM and a variable resistor depending on engine oil temperature, which works as a return voltage signal. This sensor is usually found on diesel engines.
The P0198 OBDII fault code is set because the vehicle's computer has found a high voltage condition at the Engine Oil Temperature Sensor. This is usually the result of an open circuit.
Symptoms of fault code P0198
- Check Engine light ON.
Causes of OBD2 P0198
Reasons to set the P0198 OBD2 diagnostic code:
- The engine cooling system may be damaged.
- Wires related to the EOT Sensor circuit may be in poor condition.
- The Engine Oil Temperature Sensor may be faulty.
Possible solutions of the DTC code P0198
To troubleshoot DTC P0198 OBDII, try this:
- Consult the TSB (Technical Service Bulletins).
- Check the system circuit for damage such as wear, corrosion, or burned wires or connectors. Repair or replace if necessary.
- Check that the engine temperature remains within normal operating levels. If it is overheated, inspect the entire cooling system for damage. Make any necessary repairs.
- Unplug the EOT Sensor and use a multimeter to measure the resistance between its two terminals. Start the engine and observe if the value shown on the multimeter drops smoothly as the engine temperature rises. If the resistance does not decrease as the temperature rises, the sensor is faulty, replace it.