What P0197 means
P means powertrain (engine and transmission). The 0 marks a generic code defined by SAE, so the same number means the same thing across makes. The third character, 1, places it in the fuel and air metering subsystem; the last two digits identify the specific fault.
The oil temperature sensor reports engine oil temperature. Engines that use it may adjust variable valve timing, cooling, warm-up strategy or service-interval calculations from it, and protect the engine if oil runs too hot.
What “Circuit Low” means here
"Low" means the signal or control voltage fell below the minimum the module expects. On a temperature sensor of this type (a thermistor fed from a 5 V reference through a resistor in the module), low signal voltage reads as a very high temperature. The usual explanations are a signal wire shorted to ground or a sensor that has failed internally shorted.
What you may notice
Symptoms depend on the vehicle and on how the module responds to the fault. Any of these can accompany P0197:
- Often no noticeable symptom
- Oil temperature gauge or warning behaving oddly
- Variable valve timing behaving differently when warm
Where to start diagnosing P0197
- Check the oil level and condition.
- On a cold-soaked engine, oil temperature should read close to coolant temperature and ambient.
- Inspect the sensor connector for oil seepage, which is common where the sensor threads into an oil gallery.
Clear the code only after recording freeze frame data: it shows the engine speed, load and temperature at the moment the fault set, which is often the best clue to reproducing it.
Live data to watch
These standard OBD2 values relate to P0197. Support varies by vehicle; a value your car does not report will simply be missing.
| Value | What to look for |
|---|---|
| Engine oil temperature (PID 0x5C) | Should rise more slowly than coolant temperature and settle at a stable value. |
| Engine coolant temperature (PID 0x05) | Comparison point. |
Related codes
Codes from the same engine oil temperature sensor family. If several are stored together, the shared part — wiring, a common reference voltage, or the component itself — is the place to start.
Further reading
Frequently Asked Questions
What does P0197 mean?
P0197 is the generic SAE J2012 code for "Engine Oil Temperature Sensor Circuit Low". In plain terms, it means the engine computer has detected a "circuit low" fault on the engine oil temperature sensor.
Can I keep driving with P0197?
If an over-temperature condition is reported, stop and check oil level and cooling before driving further.
What should I check first for P0197?
Check the oil level and condition.
Definition source: SAE J2012 / ISO 15031-6 generic DTC definitions. This is the generic meaning that applies across makes; a manufacturer can define a code more narrowly or add its own sub-codes, so confirm against the service information for your vehicle before replacing parts. Written by the OBDAssistant engineering team — see our editorial policy.