OBD-II Code
P0197
Severity
Not yet reviewed
Nobody on our side has assessed this code yet, so we are not going to guess at how serious it is.
Can you drive it
We cannot say
Treat it as unknown until a shop reads it with live data. If the check-engine light is FLASHING, stop driving as soon as it is safe to — that means an active misfire, whatever the code.
Indicative cost (USD)
$90–$500
From this code's diagnostic notes. Varies by vehicle, diagnosis, parts, and local labor. This is not a repair quote.
P0197 means the engine oil temperature sensor voltage dropped below the calibrated low threshold, typically under 0.2 volts on a 0-5V circuit, which the ECU interprets as either a short to ground in the signal wire or a sensor that has failed shorted internally.
How a shop works this
Work from evidence to part, not the other way round. A code names a circuit or a symptom; it does not name the part that failed.
Note every code that is set, not just this one.
Codes that appear together usually narrow the cause faster than any one of them read alone.
Read the freeze frame — the conditions the fault was recorded under.
Cold or warm, idle or load, road speed and engine speed. A fault that only appears cold is a different fault from one that only appears under load, even with the same code on the scanner.
Confirm the fault is current rather than history.
Clear the code and see whether it returns under those same conditions. A code that does not come back may have been logged during a repair, a flat battery, or a bad connection that has since been disturbed.
Then follow the diagnostic notes further down this page, in the order they are written.
They are written in the order a shop works this code, cheapest checks first. Where they name a component, inspect its wiring and connector before replacing it.
If the code comes back after a repair, the underlying fault is still there. That is the point to bring in a scanner with live data and freeze-frame, or a shop that has one.
Common symptoms
- Check engine light
Read the full diagnostic procedureP0197 means the engine oil temperature sensor voltage dropped below the calibrated low threshold, typically under 0.2 volts on a 0-5V circuit, which…
P0197 means the engine oil temperature sensor voltage dropped below the calibrated low threshold, typically under 0.2 volts on a 0-5V circuit, which the ECU interprets as either a short to ground in the signal wire or a sensor that has failed shorted internally. A short-to-ground EOT sensor reads as if the oil were extremely hot (above 300°F) because most thermistor-style EOT sensors are negative-temperature-coefficient devices — resistance drops as temperature rises, so a zero-ohm short looks identical to infinitely-hot oil.
Cheapest first
- scan EOT live data with key-on-engine-off and engine cold — the reading should be near ambient temperature (60-80°F in a normal shop bay); if the scanner shows 300°F+ on a cold engine, the circuit is shorted to ground.
- Disconnect the sensor at its connector.
- If the scanner now reads -40°F (open circuit), the sensor itself is shorted and replacement clears the code.
- If the scanner still reads 300°F+ with the sensor disconnected, the short is in the harness — back-probe the signal wire and ohm it to ground; under 1,000 ohms confirms a harness short.
- Common short locations: harness rub against the engine block, exhaust manifold heat damage, or pinched wire at a bracket.
- The expensive misdiagnosis: replacing the sensor twice while ignoring a chewed harness behind the valve cover that's grounding the signal wire to the head.
Vehicle-specific patterns2003-2010 Ford 6.0L Power Stroke throws P0197 from EOT sensor failure or harness short at the back of the engine; the sensor location makes access di…
- 2003-2010Ford 6.0L Power Stroke throws P0197 from EOT sensor failure or harness short at the back of the engine; the sensor location makes access difficult and many shops misdiagnose as a wiring fault.
- 2011-2019Ford 6.7L Power Stroke sees P0197 from a shorted EOT sensor integrated into the oil-cooler housing on the valley of the engine — replacing requires partial intake removal.
- 2010-2017BMW N55 / N20 sets P0197 from oil-filter-housing-gasket leak saturating the EOT connector with oil, corroding the pins, and creating a short to ground through the corroded contact.
- 2014-2019GM Duramax L5P / 6.2L L86 throws P0197 from EOT sensor circuit short, often resolved by replacing the connector pigtail and dielectric-greasing the new connection.
Estimated repair$90 to $500.
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