Engine Oil Temperature Sensor Low
The P0197 code means the vehicle's onboard diagnostic system has detected: Engine Oil Temperature Sensor Low. This is a moderate severity code.
- Keep driving?
- Short distances only
- DIY difficulty
- moderate
- Estimated cost
- $50 - $250 (oil temp sensor $25-$80; wiring repair $50-$100; labor $50-$150)
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Common Symptoms
- Check Engine Light on
- Oil temperature reads excessively high on scan tool
- Cooling fan may run continuously
- Transmission may avoid higher gears (protective mode)
- Possible reduced engine performance
Probable Causes (Ranked by Likelihood)
- Shorted oil temperature sensor (internally or to ground) Very High
- Short to ground in the sensor wiring High
- Corroded connector with water bridging pins Moderate
- Damaged wiring insulation touching metal Moderate
- PCM input fault Low
Step-by-Step Diagnostic Procedure
-
Read oil temperature on a scan tool. A reading of 280+ degrees F with the engine cold confirms a low circuit (shorted) condition.
-
Disconnect the sensor. If the reading jumps to -40 degrees F, the sensor is shorted internally.
-
With the sensor disconnected, check the signal wire for a short to ground (should be infinite resistance to ground).
-
Inspect the connector for moisture, corrosion, or contamination that could short the pins.
-
Check wiring insulation for damage where it contacts engine components.
Frequently Asked Questions
Can I drive with code P0197?
You can drive short distances, but systems that rely on oil temperature may behave abnormally. The cooling fan may run non-stop and the transmission may stay in lower gears as a protective measure.
Why does low circuit mean high temperature?
Oil temperature sensors use NTC (Negative Temperature Coefficient) thermistors. Lower resistance equals lower voltage equals higher temperature reading. A short to ground mimics very low resistance, making the PCM think the oil is extremely hot.
Will a low circuit cause the engine to overheat?
No. The actual oil temperature is fine -- only the sensor reading is wrong. The cooling fan may run unnecessarily, but this will not cause overheating. However, transmission shift patterns may be affected.
Sources
This page is built from documented references. Verify against your own service info before repair work.
P0197 on Diesel, EV & Equipment
The same code ID appears across other engines and platforms. The diagnostic flow varies by manufacturer — these are the platform-specific breakdowns:
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