Many modern engines track oil temperature as well as coolant temperature. The engine computer uses it to protect the engine, run variable valve timing and estimate oil life. A P0195 code means the engine computer found a problem in the engine oil temperature sensor circuit.
This guide explains what the sensor does, why oil leaks often cause this code and how to test the circuit.
P0195 Code Breakdown
Every OBD-II code follows the same five-character pattern set by the SAE J2012 standard. Each character narrows down which system has the fault. This table shows what each part of the code tells you.
| Character | Meaning | What It Tells You |
|---|---|---|
| P | Powertrain | The fault is in the engine or transmission systems. |
| 0 | Generic (SAE) code | The definition is the same on every OBD-II vehicle. |
| 1 | Fuel and air metering | The fault involves the sensors that measure air and fuel. |
| 95 | Specific fault | Engine Oil Temperature Sensor Malfunction |
What the P0195 Code Means
The SAE J2012 standard defines the P0195 code as Engine Oil Temperature Sensor Malfunction. The engine oil temperature (EOT) sensor is a thermistor, a resistor that changes value with heat. Its resistance drops as the oil gets hotter.
The powertrain control module (PCM) sends the sensor a 5-volt reference and reads the voltage that returns. High voltage means cold oil, and low voltage means hot oil. The PCM may use the reading to control variable valve timing, adjust the cooling fans, protect the engine from overheating oil and calculate the oil life monitor.
The sensor usually threads into the oil pan, the oil filter housing or the engine block near an oil passage. This code sets when the circuit shows a fault that does not fit a simple high or low reading.
Symptoms of an Oil Temperature Sensor Fault
Many engines run normally with this code. Common signs of a P0195 code include:
- Check engine light on
- Oil temperature gauge reading wrong or missing
- Oil life monitor acting oddly
- Cooling fans running more than usual
- Variable valve timing codes on some engines
- Oil around the sensor or its connector
What Causes the P0195 Code?
The sensor sits in hot oil, which is hard on its seal and connector. These are the usual causes:
- Oil leaking into the connector. A worn sensor seal can let oil seep into the pins.
- Loose or corroded connector. Heat and road spray weaken the pins.
- Damaged wiring. Wires near the oil pan can be hit by road debris.
- Failed oil temperature sensor. The thermistor can crack or wear out.
- Shorted 5-volt reference. Another sensor on the same reference can drag it down.
- PCM fault. Rare.
How to Diagnose the P0195 Code
You need a scan tool, a digital multimeter and the wiring diagram. Start with a cold engine.
Compare Readings After a Cold Soak
Let the vehicle sit overnight. Before starting, compare oil temperature with coolant and intake air temperatures. They should agree within about 10°F to 15°F. A reading of -40°F, an extreme hot value or a missing value confirms a circuit fault.
Inspect for Oil Leaks
Look at the sensor and its connector. Oil around the base or inside the connector is a common cause. Oil can wick up the wires and into the plug, causing high resistance or shorts.
Test the Circuit
Unplug the sensor with the key on. The reference should read close to 5 volts, and the ground should read close to 0 volts. Measure the sensor’s resistance and compare it with the chart in your service manual at the current oil temperature.
Repairs That Fix the P0195 Code
Match the repair to your test results, then clear the code and drive through a full warm-up.
- Replace a leaking sensor and clean oil out of the connector with electrical contact cleaner.
- Clean or replace the connector if pins are corroded or oil-soaked.
- Repair damaged wiring with solder and heat shrink tubing.
- Fix a shorted reference by finding the sensor that drags it down.
- Replace the oil temperature sensor if its resistance is out of spec.
Some sensors thread into the oil pan or filter housing, so a little oil will drain when you remove them. Have a pan ready, and check the oil level after the repair.
Repair Cost Breakdown
Most P0195 code repairs are affordable. This table shows typical ranges.
| Repair | DIY Cost | Typical Shop Cost |
|---|---|---|
| Connector cleaning or pigtail | $10 to $40 | $75 to $200 |
| Wiring repair | $10 to $30 | $100 to $300 |
| Oil temperature sensor | $20 to $80 | $100 to $250 |
| Oil top-off after replacement | $5 to $15 | Usually included |
Is It Safe to Drive with a P0195 Code?
You can usually drive with this code. The PCM uses coolant temperature or a default value in place of oil temperature.
The engine loses one of its protections against overheated oil, though, and some engines run the cooling fans more or limit valve timing. If the sensor is leaking oil, check your oil level often until it is fixed.
Related Codes
These codes often show up with this one or point to the same system:
| Code | Meaning |
|---|---|
| P0192 | Fuel Rail Pressure Sensor Circuit Low Input |
| P0193 | Fuel Rail Pressure Sensor Circuit High Input |
| P0194 | Fuel Rail Pressure Sensor Circuit Intermittent |
| P0196 | Engine Oil Temperature Sensor Range/Performance |
| P0197 | Engine Oil Temperature Sensor Low |
Getting the Oil Temperature Reading Back
A P0195 code means the PCM found a fault in the engine oil temperature sensor circuit. Oil-soaked connectors, damaged wiring and failed sensors cause most cases.
- Compare oil, coolant and intake air temperatures after a cold soak.
- Look for oil in the connector.
- Test the reference, ground and sensor resistance.
- Replace the sensor and clean the connector if oil got in.
Frequently Asked Questions
Where Is the Oil Temperature Sensor?
It usually threads into the oil pan, the oil filter housing or the engine block near an oil passage. On some engines, it is combined with the oil pressure sensor. Your service manual shows the exact location for your engine.
Why Does Oil Get into the Connector?
The sensor seals against the engine with a gasket or thread sealant. As it ages, oil can seep past the sensor body and travel up the wires by capillary action. That oil collects in the connector and can disrupt the signal.
Is the Oil Temperature Sensor the Same as the Oil Pressure Sensor?
No, they measure different things. One reads how hot the oil is, and the other reads how hard the pump pushes it. Some engines combine both in one part, though. Check the part number before you buy a replacement.
Can Low Oil Cause the P0195 Code?
A low oil level does not usually set a circuit code. However, if the sensor sits above the oil level, it may read air temperature instead of oil, which can set a range code. Always check the oil level when you diagnose oil temperature codes.