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P0298 OBD-II Trouble Code: Engine Oil Over Temperature Condition

Check Engine Light

P0298 code definition

The P0298 code is stored when the PCM detects that the engine is or has recently overheated, according to a signal from the engine oil temperature sensor.

What the P0298 code means

During engine operation, the engine oil temperature sensor is used by the PCM to ensure that the engine is operating without getting too hot. Operating a vehicle when it is overheating can lead to major engine failure, so this is a very important function of the PCM. If the engine oil temperature sensor indicates that the engine oil is too hot (and therefore, the engine is too hot), the PCM will store the P0298 code.

What causes the P0298 code?

If an engine is overheating, the most likely cause is a low engine coolant level. However, faulty cooling fans, cracked cylinder heads, a faulty thermostat, or a faulty radiator can all cause an engine to overheat.

If the code was stored when the engine had not overheated, it could be due to another cause, such as:

  • Faulty coolant temperature sensor
  • Open or shorted electrical components
  • Faulty PCM

These possible causes are very rare, and none of these parts should be replaced without first testing for the most likely causes leading to an engine overheating.

What are the symptoms of the P0298 code?

There may be no symptoms at all beyond the illumination of the Check Engine Light; however, in many cases, there will be smoke coming from the engine; the engine may make “burping” or “ticking” noises; or the engine may be disabled entirely if the vehicle model includes certain safety features.

How does a mechanic diagnose the P0298 code?

After an OBD-II scanner detects the P0298 code, the mechanic should begin with a chemical block test. This test can help provide a comparison reading, so that after the mechanic replaces any components (such as the thermostat, water pump, radiator, etc.), the reading can be checked again to ensure that the repair fixed the issue.

After this data is gathered, the mechanic should begin using a cooling system pressure tester to find a coolant leak. If this coolant leak is not found, then the mechanic should continue testing other components, such as the thermostat, cooling fan, or radiator, until they find the component that is not giving a voltage reading within the manufacturer’s specifications.

After any repair is attempted, the mechanic should be sure to clear the code from the PCM and retest the system, to be sure that the repair actually fixed the issue.

Common mistakes when diagnosing the P0298 code

Most of the time, common misdiagnoses with the P0298 code come from replacing parts without performing a thorough system check. For example: many technicians will replace leaking cooling system components, instead of checking the entire cooling system for issues. While these parts likely needed the replacement, a full system check can reveal underlying issues that will ruin the replacement components the same way they did the leaking components.

How serious is the P0298 code?

If the P0298 code is being detected, the vehicle must be repaired as soon as possible. This code represents a very serious issue that can lead to unsafe driving conditions, or to major engine failure if left unchecked.

What repairs can fix the P0298 code?

There are many steps that a technician will likely have to follow in order to fully address a P0298 code detection. They include:

Need help with a P0298 code?

YourMechanic offers certified mobile mechanics who will come to your home or office to diagnose and repair your vehicle. Get a quote and book an appointment online or speak to a service advisor at 1-800-701-6230.

The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details
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