Oil Pressure Sensor Guide

One internal component that you probably don't think of very often is the engine oil pressure sensor. However, the oil pressure sensor is a fundamental part of the internal combustion engine. 

It's also sometimes called an oil pressure sending unit or oil pressure switch (OPS). Its purpose is to keep an eye on the oil pressure in your engine. Oil pressure must be kept at certain levels to ensure that oil is reaching all the vital parts of your engine.

What Does the Oil Pressure Sensor Do?

An oil pressure sensor is a simple device that activates a warning light on your dash when your engine's oil pressure is not in line with set levels. This is a very simple device made up of a spring-loaded switch and a diaphragm. The diaphragm receives oil and is designed to stay open at a set pressure level.

The pressure pushes the diaphragm into the switch and keeps the warning light off. If the pressure level isn't met, then the switch will trigger the light on your dash. Generally speaking, the oil pressure sensor is there to recognize low oil pressure, not high oil pressure.

Low oil pressure can cause serious damage to your engine and might be the result of a clogged oil filter, a faulty oil pump, or other reasons. The purpose of the oil sensor is to give you enough warning to shut your engine off before any of these things cause real damage.

How Does an Oil Pressure Sensor Work?

Most oil pressure sensors are the simple switch-type described in the previous section. The switch opens the electrical circuit if a minimum oil pressure level exists. Another version is an actual sensor that measures oil pressure.

For the switch version, you may see the warning light on your dash when the ignition is on but not when the engine is off. This is because the switch needs oil pressure to open. When the engine is started, the oil pump begins building pressure. As soon as the minimum pressure is reached, the switch opens and your warning light will turn off.

Oil Pressure Sensor Guide

Where Is the Oil Pressure Sensor?

The oil pressure switch or sensor is generally located in the cylinder block near the oil filter or oil filter housing. Older vehicles usually have the OPS directly wired to the oil pressure gauge. One side of the gauge gets battery power and the OPS has a ground on the other side.

On newer vehicles, the OPS operates a bit differently. Typically, the sensor is hooked up to the electronic control module. It measures actual oil pressure and forwards the information to the engine's computer. Oil pressure sensors are designed to last for the life of the vehicle, but there's always a possibility that they can fail.

Oil Pressure Sensor Problems

The OPS can develop certain problems. One common problem is when the switch starts to leak oil. It might leak from the actual sensor or from the tread. The tread can be resealed, but if the actual sensor is leaking, then it will need to be replaced.

Another issue is when the OPS gets clogged or has some other internal failure that renders it unable to properly read the oil pressure. That can result in the dash warning light coming on even if the oil pressure is fine.

How To Test The Oil Pressure Sensor

The testing procedure is different depending on what type of OPS your engine has. The first step is to check the engine oil level and quality. Low oil pressure lights often come on due to an inadequate oil level.

The light might also come on if the oil is extremely old and degraded in quality. Otherwise, the sensor's wiring needs to be tested and the actual oil pressure of the engine should be tested. To measure oil pressure, you'll need an oil pressure gauge that uses a special adaptor to connect where the original OPS would connect.

If the oil pressure shows up as low with the engine on, then it's an actual engine problem. If the pressure is within correct levels, and the sensor wiring is ok, then the problem is the actual sensor.

How To Replace An Oil Pressure Sensor

The oil pressure test is quite time-consuming and oil pressure sensors are not very expensive, so you'll often find mechanics advising customers to simply replace the sensor.

If you can replace your oil sensor for between $100 and $150 and it solves the problem, you've potentially saved yourself additional time for a DIY job or additional labor costs for going to a mechanic.

How To Reset the Oil Pressure Sensor Light

After performing maintenance, it's possible that you'll need to reset your oil pressure sensor light. If this is an issue in your vehicle, follow these steps to reset it:

  • Step 1 - Put your key into the ignition and turn it to the on position without starting the engine.
  • Step 2 - Slowly press the gas pedal three times in a row within 10 seconds. This should reset the system.
  • Step 3 - Verify the reset by turning the ignition off and then on again.

One of the issues leading to an oil pressure warning light is low oil or degraded oil. Keep up with your oil changes by using an oil change kit from Power Oil Center. Our DIY oil change kits contain everything you need to change your oil in your driveway or garage.

Oil is the lifeblood of your engine, don't let your vehicle go too long without an oil change. Our oil change kits even come with reminder stickers to make sure that you won't miss a change date.