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P0195 Code Explained: Engine Oil Temperature Sensor Circuit Malfunction Causes, Symptoms & Fixes

P0195 code illustration showing an Engine Oil Temperature Sensor circuit malfunction with damaged wiring, Check Engine Light, Pro Street TV logo, and www.ProStreetOnline.com.

If your OBD-II scanner displays P0195, your vehicle’s Engine Control Module (ECM) or Powertrain Control Module (PCM) has detected an electrical malfunction within the Engine Oil Temperature (EOT) Sensor circuit.

The generic OBD-II definition for P0195 is:

Engine Oil Temperature Sensor Circuit Malfunction

Unlike P0196, which indicates a range or performance issue, P0197, which indicates a low-input condition, P0198, which indicates a high-input condition, or P0199, which indicates an intermittent signal, P0195 means the PCM has detected a general fault within the Engine Oil Temperature Sensor circuit but cannot determine the exact electrical failure.

Modern engines use Engine Oil Temperature information to control:

Common causes include:

Because the PCM can no longer rely on accurate engine oil temperature information, it may substitute a default value while illuminating the Check Engine Light.

What Does the P0195 Code Mean?

The PCM continuously monitors the Engine Oil Temperature Sensor by supplying a reference voltage and monitoring the returning signal.

Engine oil temperature information helps manage:

If the PCM detects an electrical fault anywhere within the Engine Oil Temperature Sensor circuit, it stores P0195.

Unlike the other Engine Oil Temperature Sensor codes, P0195 does not identify whether the signal is too high, too low, intermittent, or simply implausible. It only indicates that the circuit is not operating correctly.

What Is the Engine Oil Temperature Sensor?

The Engine Oil Temperature (EOT) Sensor is a thermistor whose electrical resistance changes according to engine oil temperature.

Depending on the engine design, it may be located:

As oil temperature changes, sensor resistance changes, allowing the PCM to calculate engine oil temperature accurately.

Reliable oil temperature information helps maximize engine life while improving performance and fuel economy.

Why Engine Oil Temperature Matters

Engine oil performs several essential functions:

Oil that becomes excessively hot may:

Oil that remains excessively cold may:

Accurate oil temperature data allows the PCM to make proper engine management decisions under all operating conditions.

How the PCM Detects P0195

The PCM continuously monitors:

If the PCM detects an abnormal electrical condition that prevents reliable Engine Oil Temperature Sensor operation, it stores P0195.

Most manufacturers require the fault to occur during multiple monitoring events before illuminating the Check Engine Light.

What Does “Circuit Malfunction” Mean?

A Circuit Malfunction code indicates the PCM has detected an electrical problem somewhere within the Engine Oil Temperature Sensor circuit.

Unlike P0197 or P0198, P0195 does not identify whether the signal is too high or too low.

Possible causes include:

Additional testing is required to determine the exact cause.

Can Wiring Problems Cause P0195?

Absolutely.

Electrical wiring faults are one of the most common causes of P0195.

Inspect for:

Even a small amount of connector corrosion can interfere with accurate sensor communication.

Can the Engine Oil Temperature Sensor Fail?

Yes.

Engine Oil Temperature Sensors operate in harsh environments exposed to:

Over time they may fail because of:

A failed sensor may stop communicating correctly with the PCM or send inaccurate electrical signals.

Can Low Engine Oil Cause P0195?

Not directly.

Although low engine oil may affect actual oil temperature, it generally does not create an electrical circuit malfunction.

However, low engine oil may contribute to:

Always verify engine oil level and condition during diagnosis.

P0195 Quick Facts

ItemInformation
DTCP0195
Generic DefinitionEngine Oil Temperature Sensor Circuit Malfunction
SystemEngine Management
SeverityModerate
Safe to Drive?Limited driving recommended
Common SymptomsCheck Engine Light, poor fuel economy, reduced engine performance
Common CausesFailed EOT sensor, damaged wiring, connector corrosion, circuit faults
Typical Repair Cost$100–900+
Related CodesP0196, P0197, P0198, P0199

Common Vehicles That Experience P0195

P0195 commonly appears on:

The code is especially common on:

What Does P0195 Really Mean?

The wording of P0195 often causes drivers to believe the Engine Oil Temperature Sensor has completely failed.

The code does not automatically mean:

Instead, it means the PCM has detected an electrical malfunction somewhere within the Engine Oil Temperature Sensor circuit.

The underlying problem may involve:

Think of P0195 as the PCM saying:

“Something is wrong with the oil temperature sensor circuit. I know the conversation isn’t making sense—I just don’t know yet whether the sensor, wiring, or connector is the one causing the confusion.”

Common P0195 Scan Tool Patterns

Using a professional scan tool is one of the fastest ways to diagnose P0195.

Unlike P0196, which indicates a range or performance problem, P0197, which indicates a low-voltage condition, P0198, which indicates a high-voltage condition, or P0199, which indicates an intermittent signal, P0195 means the PCM has detected a general electrical malfunction somewhere within the Engine Oil Temperature (EOT) Sensor circuit.

Modern scan tools may display:

Comparing Engine Oil Temperature with Engine Coolant Temperature is one of the quickest ways to determine whether the problem is electrical or mechanical.

Pattern 1: No Engine Oil Temperature Reading

One of the most common scan-tool patterns is:

Possible causes include:

When communication is lost entirely, many PCMs substitute a default oil temperature value.

Pattern 2: Engine Oil Temperature Is Implausible

The scan tool may display:

Possible causes include:

Although P0196 is reserved for range/performance problems, some manufacturers initially store P0195 when sensor data becomes unreliable.

Pattern 3: Engine Oil Temperature Does Not Respond

The scan tool may display:

Possible causes include:

A properly functioning Engine Oil Temperature Sensor should respond gradually as oil temperature changes.

Pattern 4: Reduced Engine Performance

Some manufacturers activate engine protection strategies whenever reliable Engine Oil Temperature data is unavailable.

Drivers may notice:

These strategies help protect the engine until valid temperature information is restored.

Pattern 5: Multiple Temperature Sensor Codes

P0195 commonly appears together with:

Multiple temperature-related codes often indicate:

Pattern 6: Cooling Fan Operates Unexpectedly

Some vehicles may:

Without reliable oil temperature information, the PCM may default to protective cooling strategies.

Pattern 7: Freeze-Frame Data Shows Abnormal Temperature Information

Freeze-frame data may reveal:

This information often helps determine whether the fault is electrical or mechanical.

Common Symptoms of P0195

Symptoms vary depending on the vehicle and engine management strategy.

Common symptoms include:

Some vehicles exhibit no noticeable drivability problems beyond the Check Engine Light.

Check Engine Light

The Check Engine Light is usually the first symptom.

Most manufacturers require:

before storing P0195.

Reduced Engine Performance

Drivers may notice:

The PCM may limit engine performance whenever reliable oil temperature data is unavailable.

Poor Fuel Economy

Incorrect Engine Oil Temperature information may cause:

Fuel economy often decreases gradually.

Increased Emissions

Without accurate oil temperature information, the PCM may:

Vehicles may fail emissions inspections if the condition persists.

Is P0195 Serious?

P0195 is generally considered a moderate severity diagnostic trouble code.

Ignoring the problem may eventually result in:

If the underlying problem involves overheating or lubrication issues, engine damage may occur if left unresolved.

Can You Drive With P0195?

Limited driving is usually possible, but repairs should be completed as soon as practical.

Driving may be acceptable if:

Stop driving immediately if:

P0195 vs Related Trouble Codes

Understanding related Engine Oil Temperature Sensor codes simplifies diagnosis.

P0195

Engine Oil Temperature Sensor Circuit Malfunction

The PCM detects a general electrical fault within the Engine Oil Temperature Sensor circuit.

P0196

Engine Oil Temperature Sensor Range/Performance

The sensor communicates, but reported temperature values are implausible.

P0197

Engine Oil Temperature Sensor Circuit Low Input

The PCM detects sensor voltage below specification.

P0198

Engine Oil Temperature Sensor Circuit High Input

The PCM detects sensor voltage above specification.

P0199

Engine Oil Temperature Sensor Circuit Intermittent

The PCM detects unstable or intermittent sensor communication.

30 Common Causes of P0195

The most common causes include:

  1. Failed Engine Oil Temperature Sensor
  2. Damaged wiring
  3. Open circuit
  4. Short-to-ground
  5. Short-to-voltage
  6. Loose electrical connector
  7. Connector corrosion
  8. Broken signal wire
  9. Melted wiring insulation
  10. Pinched wiring harness
  11. Poor ground connection
  12. High-resistance wiring
  13. Oil contamination inside connector
  14. Moisture intrusion
  15. Heat-damaged wiring
  16. Rodent damage
  17. Bent connector terminals
  18. Failed 5-volt reference circuit
  19. Internal sensor failure
  20. Incorrect replacement sensor
  21. Previous wiring repairs
  22. Harness routing problems
  23. Charging system voltage problems
  24. Electrical interference
  25. Cooling system issues
  26. Engine overheating
  27. PCM software issue
  28. Loose PCM connector
  29. Failed PCM (rare)
  30. Manufacturing defect

Final Thoughts

The P0195 Engine Oil Temperature Sensor Circuit Malfunction code indicates the PCM has detected an electrical fault somewhere within the Engine Oil Temperature Sensor circuit. In most cases, the root cause is a failed Engine Oil Temperature Sensor, damaged wiring, loose connector, connector corrosion, poor ground connection, or reference voltage problem, rather than PCM failure.

Proper diagnosis should determine whether the fault originates in:

The next section of this guide covers:

Following a systematic diagnostic process prevents unnecessary parts replacement while restoring accurate engine oil temperature monitoring, proper engine protection, fuel economy, emissions compliance, and long-term reliability.

Related Pro Street Diagnostic Guides

How to Diagnose the P0195 Code

Diagnosing P0195 requires determining why the Engine Oil Temperature (EOT) Sensor circuit is no longer communicating properly with the Powertrain Control Module (PCM).

Unlike P0196, which indicates a range or performance problem, P0197, which indicates a low-voltage condition, P0198, which indicates a high-voltage condition, or P0199, which indicates an intermittent signal, P0195 indicates a general electrical malfunction somewhere within the Engine Oil Temperature Sensor circuit.

The underlying problem may involve:

Because P0195 is a general circuit fault, diagnosis should begin with the entire electrical circuit rather than immediately replacing the sensor.

Safety Precautions

Before beginning diagnosis:

Engine oil temperatures may exceed 250°F (121°C) after normal driving.

Tools Required

Professional diagnosis may require:

A scan tool capable of displaying Engine Oil Temperature (EOT) and Engine Coolant Temperature (ECT) simultaneously is highly recommended.

Step 1 – Verify the Code

Connect a professional scan tool.

Record:

Monitor:

Never erase diagnostic trouble codes before recording freeze-frame data.

Step 2 – Check for Related Trouble Codes

P0195 commonly appears with:

Related temperature sensor codes often simplify diagnosis.

Code CombinationLikely Diagnosis
P0195 onlyGeneral Engine Oil Temperature Sensor circuit fault
P0195 + P0196Sensor performance problem
P0195 + P0197Low-voltage circuit fault
P0195 + P0198High-voltage circuit fault
P0195 + P0199Intermittent wiring or connector problem
P0195 + P0116Cooling system or temperature correlation issue

Repair obvious electrical faults before replacing the Engine Oil Temperature Sensor.

Step 3 – Review Freeze-Frame Data

Review:

Freeze-frame data often identifies the operating conditions present when the PCM detected the circuit malfunction.

Step 4 – Verify Engine Oil Level and Condition

Before electrical testing:

Inspect:

Although engine oil condition rarely creates an electrical fault, correcting maintenance problems eliminates additional variables during diagnosis.

Step 5 – Inspect the Engine Oil Temperature Sensor

Locate the Engine Oil Temperature Sensor.

Inspect for:

Replace any sensor showing obvious physical damage before continuing.

Step 6 – Inspect the Wiring Harness

Inspect the wiring between the Engine Oil Temperature Sensor and the PCM.

Look for:

Most P0195 failures originate from damaged wiring rather than PCM failure.

Step 7 – Inspect the Electrical Connector

Disconnect the sensor connector.

Inspect for:

Connector corrosion is one of the most common causes of Engine Oil Temperature Sensor circuit failures.

Step 8 – Verify Reference Voltage

Using a digital multimeter:

Measure:

Compare readings with manufacturer specifications.

If reference voltage is missing or incorrect:

Inspect:

Step 9 – Verify Ground Integrity

Measure voltage drop across the sensor ground.

Inspect for:

Poor ground integrity frequently causes temperature sensor circuit faults.

Step 10 – Measure Engine Oil Temperature Sensor Voltage

Reconnect the sensor.

Back-probe the signal wire.

Verify:

If voltage remains fixed, disappears, or behaves erratically:

Suspect:

Step 11 – Compare Engine Oil Temperature With Coolant Temperature

After warm-up compare:

Normally:

Large differences may indicate:

Step 12 – Verify Actual Oil Temperature

Use an infrared thermometer to measure:

Compare these readings with scan-tool data.

If actual oil temperature differs significantly from scan-tool readings:

Suspect:

Step 13 – Inspect the Cooling System

Verify:

Cooling system problems should always be corrected before final diagnosis.

Step 14 – Review Technical Service Bulletins

Before replacing expensive components:

Review manufacturer Technical Service Bulletins (TSBs).

Look for:

Some manufacturers have released updated calibrations to reduce false Engine Oil Temperature Sensor circuit faults.

Step 15 – Verify Charging System Voltage

Measure charging voltage.

Normal charging voltage:

13.5–14.8 volts

Charging system faults can affect reference voltage and sensor operation.

Step 16 – Inspect PCM Connector Pins

Inspect PCM connectors for:

Poor PCM connections may interrupt Engine Oil Temperature Sensor communication.

Step 17 – Perform a Wiggle Test

While monitoring live Engine Oil Temperature data:

Move:

Watch for:

Unexpected changes indicate wiring or connector problems.

Step 18 – Perform a Road Test

Drive the vehicle while monitoring:

Verify Engine Oil Temperature responds smoothly under:

Step 19 – Verify Sensor Response

Observe how Engine Oil Temperature changes during:

A properly functioning Engine Oil Temperature Sensor should respond smoothly and consistently throughout the entire drive cycle.

Step 20 – Confirm the Diagnosis

Before replacing major components, verify:

Completing these diagnostic procedures prevents unnecessary parts replacement while accurately identifying the root cause of P0195.

Step 21 – Replace the Engine Oil Temperature Sensor

If testing confirms the Engine Oil Temperature (EOT) Sensor has failed, replacement is the proper repair.

General replacement procedure:

  1. Allow the engine to cool completely.
  2. Disconnect the negative battery cable.
  3. Locate the Engine Oil Temperature Sensor.
  4. Disconnect the electrical connector.
  5. Remove the sensor using the proper socket.
  6. Inspect the sealing washer or O-ring.
  7. Install an OEM-quality replacement sensor.
  8. Torque the sensor to manufacturer specifications.
  9. Reconnect the electrical connector.
  10. Clear all diagnostic trouble codes.
  11. Verify proper Engine Oil Temperature operation using a professional scan tool.

Whenever possible, install an OEM or high-quality replacement sensor, as inexpensive aftermarket sensors are a common cause of repeat failures.

Step 22 – Repair Wiring Problems

Electrical wiring failures account for a large percentage of P0195 repairs.

Inspect and repair:

For permanent repairs:

Poor-quality wiring repairs frequently result in recurring diagnostic trouble codes.

Step 23 – Repair Electrical Connectors

Inspect every connector between the Engine Oil Temperature Sensor and the PCM.

Repair:

Many P0195 faults are caused by poor electrical contact rather than a failed sensor.

Step 24 – Repair Open or Short Circuits

Since P0195 is a general circuit malfunction, inspect the entire circuit for:

Pay close attention to wiring routed near:

Electrical circuit damage is often hidden beneath otherwise intact insulation.

Step 25 – Perform an Engine Oil Service

If the engine oil is:

Perform a complete oil and filter service using the manufacturer’s specified oil grade.

Although poor oil condition rarely causes P0195 directly, clean oil improves engine protection and ensures accurate oil temperature readings.

Step 26 – Repair Cooling System Problems

Inspect and repair:

Cooling system problems may affect engine oil temperature and should be corrected before verifying repairs.

Step 27 – Verify the 5-Volt Reference Circuit

If sensor communication remains abnormal:

Inspect:

Repair any reference voltage problems before replacing expensive electronic components.

Step 28 – Inspect PCM Connections

Inspect the PCM electrical connectors for:

Poor PCM connections can interrupt communication with the Engine Oil Temperature Sensor.

Step 29 – Update PCM Software

Before replacing the PCM:

Review all manufacturer Technical Service Bulletins (TSBs).

Some manufacturers have released PCM updates addressing:

Always verify the PCM has the latest available software.

Step 30 – Verify Proper System Operation

After repairs:

Monitor:

Perform:

Engine Oil Temperature should respond smoothly and logically throughout the drive without abnormal spikes, dropouts, or fixed readings.

How to Fix P0195

The proper repair depends entirely on the diagnostic results.

Common repairs include:

Verifying the Repair

After completing repairs:

  1. Clear all diagnostic trouble codes.
  2. Start the engine from a cold condition.
  3. Monitor Engine Oil Temperature with a scan tool.
  4. Compare Engine Oil Temperature with Engine Coolant Temperature during warm-up.
  5. Perform a complete road test.
  6. Complete an OBD-II drive cycle.
  7. Verify no pending or permanent DTCs return.
  8. Confirm realistic Engine Oil Temperature readings under idle, cruise, and heavy-load conditions.

A successful repair restores accurate oil temperature monitoring, proper engine protection, fuel economy, emissions compliance, and long-term engine reliability.

Typical Repair Costs

RepairTypical Cost
Professional diagnosis$100–250
Engine Oil Temperature Sensor replacement$150–400
Wiring repair$100–500
Connector replacement$75–250
Ground circuit repair$75–300
Engine oil and filter change$50–150
Cooling system repair$150–1,000+
PCM software update$100–250
PCM connector repair$150–500
PCM replacement$900–2,500+

Repair costs vary depending on vehicle make, engine design, and regional labor rates.

Common Diagnostic Mistakes

Avoid these common mistakes:

Most P0195 repairs involve correcting wiring or connector issues rather than replacing the PCM.

Manufacturer-Specific Notes

Ford/Lincoln

Inspect:

Power Stroke diesel and EcoBoost engines commonly experience heat-related harness failures.

General Motors (Chevrolet, GMC, Cadillac, Buick)

Verify:

Many GM vehicles compare Engine Oil Temperature with Engine Coolant Temperature to detect circuit faults.

Chrysler, Dodge, Jeep, Ram

Inspect:

Heat damage near the rear of the engine is a common failure point.

Toyota/Lexus

Inspect:

Electrical faults are significantly more common than PCM failures.

Nissan/Infiniti

Verify:

Turbocharged Nissan engines rely heavily on accurate oil temperature monitoring for engine protection.

Hyundai/Kia

Inspect:

Sensor wiring failures are considerably more common than PCM failures.

Frequently Asked Questions

What usually fixes P0195?

The most common repairs include replacing the Engine Oil Temperature Sensor, repairing damaged wiring, cleaning or replacing electrical connectors, repairing open or short circuits, restoring proper ground connections, repairing the 5-volt reference circuit, or updating PCM software.

Can I drive with P0195?

Yes, limited driving is generally safe if engine temperature and oil pressure remain normal. However, repairs should be completed promptly because inaccurate oil temperature information can affect engine management and long-term engine protection.

Does P0195 always mean the Engine Oil Temperature Sensor is bad?

No. Damaged wiring, connector corrosion, poor grounds, open circuits, short circuits, reference voltage problems, and PCM software issues can all trigger P0195 without a failed sensor.

Can bad wiring cause P0195?

Absolutely. Broken wiring, melted insulation, loose connectors, connector corrosion, damaged harnesses, and poor electrical connections are among the most common causes of P0195.

Is P0195 a serious code?

P0195 is generally considered a moderate severity diagnostic trouble code. While it may not immediately damage the engine, incorrect oil temperature information can reduce fuel economy, increase emissions, interfere with engine protection strategies, and eventually lead to more significant drivability issues if left unresolved.

Final Thoughts

The P0195 Engine Oil Temperature Sensor Circuit Malfunction code indicates the PCM has detected a general electrical fault within the Engine Oil Temperature Sensor circuit. In most cases, the root cause is a failed Engine Oil Temperature Sensor, damaged wiring, connector corrosion, poor ground connection, or reference voltage problem, not a failed PCM.

A complete diagnosis should always verify:

Following a structured diagnostic process prevents unnecessary parts replacement while restoring accurate engine oil temperature monitoring, proper engine protection, fuel economy, emissions compliance, and long-term engine reliability.

Continue Your Pro Street Temperature Sensor Series

Related guides include:

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