What causes fault code P0298?

• Most likely: Low oil level or incorrect oil weight/quality • Likely: Faulty Engine Oil Temperature (EOT) sensor or wiring issues (short circuit) • Possible: Clogged oil cooler or cooling system malfunction (e.g., faulty thermostat or water pump) • Rare: Internal engine mechanical wear generating excessive frictional heat

How do you fix fault code P0298?

STEP 1: Check oil level and condition. If oil is dark or smells burnt, perform an oil and filter change. Check for external leaks. STEP 2: Test the EOT sensor. Measure resistance (Ohms) across the sensor; at 20°C (68°F) it should typically be 2000-3000 Ohms. Verify 5V reference voltage from ECU at the connector. STEP 3: Inspect the oil cooler for external blockages (debris) and internal clogging by measuring temperature delta between inlet and outlet using an IR thermometer. STEP 4: Use a scan tool to compare oil temp vs. coolant temp on a cold start; they should be within 2-3 degrees of each other. If oil temp is implausibly high at cold start, replace the EOT sensor.

Powertrain (Engine & Gearbox)Standard EOBD

P0298 - Engine Oil Over Temperature

Q: What are the symptoms of fault code P0298?

• Check Engine Light (MIL) illuminated • 'High Oil Temperature' message on dash • Engine power reduction (Limp mode) • Abnormal engine noise under load • Smell of burnt oil

Last updated:1 February 2026

Related:Engine Oil Temperature (EOT) Sensor, Oil Cooler, Oil Filter, Engine Control Unit (ECU), Engine Coolant Thermostat

System

Powertrain (Engine & Gearbox)

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Technical Description

Diagnostic Trouble Code (DTC) P0298 is triggered when the Engine Control Unit (ECU) detects that the engine oil temperature has exceeded a predetermined safety threshold for a specific duration. The system utilizes an Engine Oil Temperature (EOT) sensor, typically an NTC thermistor, to monitor lubricant thermal status. Excessive oil temperature leads to a reduction in viscosity and film strength, risking mechanical failure of bearings and cylinder walls. This code may trigger 'Limp Home Mode' to reduce engine load and protect internal components. The ECU communicates this status via the CAN-bus to the instrument cluster to illuminate warning lamps.

Possible Causes

Low oil level or incorrect oil weight/quality

Faulty Engine Oil Temperature (EOT) sensor or wiring issues (short circuit)

Clogged oil cooler or cooling system malfunction (e.g., faulty thermostat or water pump)

Internal engine mechanical wear generating excessive frictional heat

Symptoms

Check Engine Light (MIL) illuminated

'High Oil Temperature' message on dash

Engine power reduction (Limp mode)

Abnormal engine noise under load

Smell of burnt oil

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P0298 - Engine Oil Over Temperature

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P0298 - Engine Oil Over Temperature

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