How to Fix P0199 Code: Dos and Don’ts – Problem Solving

OBD2 Scanners is reader-supported. When you buy through links on our site, we may earn an affiliate commission.

What do you do if your car has been exhibiting problems and the Check Engine Light has come on? Your first instinct might be to pick up an OBD scanner and see if a trouble code has popped up. If the P0199 error code does show up, you may wonder what you can do to fix it right away.

In this article, we will give you a rundown of the symptoms, causes, and the dos and don’ts of how to fix the P0199 code. So, whether you’re a mechanic or just someone who likes DIY, make sure to read on!

What is Code P0199?

The P0199 is a diagnostic trouble code (DTC) for “Engine Oil Temperature Sensor Intermittent.” This code means that the Engine Control Module (ECM) has detected an intermittent fault in the engine oil temperature sensor.

When the Engine Control Unit (ECU) sees an irregular out-of-range signal from the oil temperature sensor, Code P0199 is triggered. This code is set to prevent damage to the vehicle and will remain on until everything is fixed.

Symptoms of Code P0199

In most cases, the P0199 code does not manifest any symptoms aside from:

  • Check engine light illuminated
  • Will activate Fail-safe mode
  • Overheating due to coolant problems

Causes for Code P0199

When you experience code P0199, you may think the problem is with the oil temperature sensor, which is usually the case and replace it immediately. However, aside from faulty sensors, there are some other causes to consider in correctly diagnosing this issue. The most common reasons are:

  • Damaged oil temperature sensor
  • Poor electrical connections
  • Open/short wiring harness

How to Diagnose Error Code P0199?

When diagnosing this error code, you need to check all the possible causes of why the code P0199 has been set. By doing so, you can have an idea of where to start. There aren't many possible causes. Are you ready? Let's get started!

Check for Other Diagnostic Trouble Codes

Checking for other trouble codes is the first step. If there are other codes, this might be a symptom of another problem. So, go ahead and check for them.

  1. Connect the scanner to the diagnostic connector, save all stored trouble codes, and freeze frame data.
  2. Clear all codes, drive the vehicle and see if the code returns. If it does, it is confirmed that you have an            intermittent condition. 

Perform Visual Inspection

Next, you will need to do a visual inspection. This is pretty self-explanatory, but essentially what you want to do is look for anything that might be causing the issue. If you find any damaged wires, repair them or replace them if necessary.

Check for Open/ Short Wiring Harness

Look for open or short wiring harnesses. These can often cause P0199, so it's worth checking. Connect the multimeter to the affected wire and check for continuity. If there is no continuity, you have an open circuit. 

This means that the current cannot flow between the two points and will need to replace the affected wire. If there is continuity, then you have a short circuit. This means the current can flow between the two points and will need to repair the affected wire.

Check the Engine Oil Temperature Sensor Voltage

If you found nothing during the visual inspection and the open/short test turned out fine, you will need to test the data parameter of the engine oil temperature sensor. Using an advanced level scan tool, you can track changes in voltage and readings over time, allowing you to detect any hidden problems. To perform this:

  1. Start the engine and let it idle
  2. Connect the scan tool to the vehicle's DLC
  3. Monitor the EOT sensor PID with the scan tool
  4. Keep an eye on the voltage or reading; it should fluctuate between 0.50v and 0.70v as the engine warms        up
  5. If you see a constant voltage or reading outside this range, the sensor is faulty and will need to be                    replaced.

How to Fix Code P0199?

By this time, you probably found out the cause of P0199. If the root cause is a faulty oil temperature sensor, you need to replace it, and to do this, you will need:

  • Replacement oil temperature sensor
  • Screwdriver set
  • Rags
  • Socket and wrench set
  • Thread sealant

Step-by-Step Guide to Replacing the Oil Temperature Sensor

  1. Locate the oil temperature sensor. It's usually located on the side of the engine block near the oil filter.
  2. Next, disconnect the electrical connector from the oil temperature sensor.
  3. Use a wrench or socket to remove the sensor.
  4. Compare the old sensor to the new one as it should be the same size and shape.
  5. Install the new sensor and make sure it's adequately placed.
  6. Apply a thread sealant to the new sensor.
  7. Screw in the new sensor by hand until it's snug.
  8. Tighten the sensor with a wrench or socket until it's tight.
  9. Reconnect the electrical connector to the oil temperature sensor.
  10. Start the engine and check for leaks.

Common Mistakes When Diagnosing the Code P0199

Making mistakes when diagnosing is sometimes unavoidable, even for professional mechanics. What more if you are a first-timer. However, you can prevent making the same mistakes by avoiding doing these things:

  • Not checking for damaged wiring harness and connectors
  • Installing the new oil temperature sensor without sealing it first.
  • Tightening the sensor too much or not enough. Just make sure that it is snug.
  • Using an oil temperature sensor that is not the same as the old one.
  • Not checking for other diagnostic trouble codes.

Code P0199 FAQs

1. Is the P0199 code serious?

The risk level of this issue is moderate. If you ignore and leave this trouble code unaddressed, it can cause your engine to overheat.

2. Can I still drive having this error code?

Yes, you can drive, but since it can cause your engine to overheat, it is recommended to fix this issue first before you drive.

3. What can I do to prevent this code from coming back?

You can do a few things to prevent this error code, like regularly checking electrical wiring/harness and performing regular car maintenance.

4. Should I use an advanced OBD scanner to diagnose this trouble code?

Not necessarily, but it is best to use an advanced OBD scanner because it cannot just read codes but also provide information on what might have caused the code to trigger.

5. How much does it cost to diagnose and repair the P0199 code?

The average cost for diagnosing and repairing the P0199 code is $80-$100.


The code P0199 is considered a severe issue, but you can fix it yourself without spending too much money with the correct information. It may seem daunting to fix it at first, but by verifying all the possible causes, you can make the process much easier.

Have you ever had to deal with the P0199 trouble code? What was your experience? Let us know in the comments below!