Oil is what lubricates the parts and components of a vehicle’s engine. That way, there is less friction inside of the engine. The hardest part is figuring out the amount of oil passing through the engine. This is where the oil pressure sensor comes in handy because it can detect when there is low oil pressure in the engine.
Since the oil pressure sensor is connected to the oil pressure gauge and vehicle computer, it needs to work properly so that the computer can make sure the correct amount of oil is flowing into the engine.
How Does an Oil Pressure Sensor Work?
The oil pressure sensor (also referred to as an oil pressure sending unit or oil pressure switch) is a device that measures the amount of pressure in the engine’s oil system. When the oil pressure falls outside of a set range, it produces an alarm signal.
The spring-loaded switch and a diaphragm are two critical components to the oil pressure sensor. The pressure switch is connected to the oil gallery and is attached to an engine block.
When the oil pressure begins to build on the diaphragm, the spring pressure of the switch overcomes the force causing it to separate the electrical contacts, turning on the warning light.
The diaphragm releases pressure from the springs in order for the switch contacts that would normally display a warning signal to the driver if oil pressure falls below a set threshold.
A vehicle’s dashboard has a low oil pressure warning light. Any motorist will understand that when this light blinks rapidly, it indicates a minor drop in oil pressure. If the light remains on, the driver is notified of a total loss of oil pressure regardless.
When the engine is switched on, an electrical current goes from a fuse to the oil pressure switch, ensuring that the indicator light is turned off. When oil pressure rises above 4.3 PSI, the diaphragm separates the contacts, turning on the oil pressure light.
Oil Pressure Switch and VTEC
The variable valve timing system (VTEC) is intended to modify the volumetric efficiency of the engine, resulting in more power, by rerouting oil pressure to the rocker arm pistons over 2,500 RPM.
The VVT solenoid contains the VTEC oil pressure switch which is typically in the open position. The voltage should fall to zero as soon as the VTEC oil pressure switch closes. The ECM can determine whether oil pressure was delivered to the VTEC system in this way.
The ECM may then set a code when this system malfunctions. Diagnostic trouble codes P1253 (for the solenoid) and P1259 (for the pressure switch) are then stored in the system. Prior to condemning the solenoid or the VTEC oil pressure switch, each code needs to be further diagnosed.
Signs of a Bad Oil Pressure Sensor or Switch
If you have an oil pressure sensor that is not working correctly, then your engine may suffer the consequences because it won’t get the proper amount of oil flowing into it.
Below are the top 3 symptoms you can expect to see when there is a bad oil pressure sensor in your vehicle.
1) Blinking Oil Pressure Light
If you see the oil pressure light blinking constantly and not staying consistently on or consistently off, then this is an early warning sign that your oil pressure sensor is about to go out.
This is something you do not want to let go on for very long because you need to know that correct amount of oil pressure that you have. If you end up with low oil in your vehicle and you don’t know it, this could severely damage your engine.
Therefore, never let this go to chance. Replace the oil pressure sensor right away.
2) Oil Pressure Light Turns On
If the oil pressure light in your dashboard turns on and stays on, the first thing you might think is that you have a low level of oil in your vehicle. So naturally, you’ll want to check how much oil you have in your engine and make sure that it is at the proper level.
If you find the oil level to be normal while your oil pressure light is still on, then it’s likely a problem with your oil pressure sensor. If you don’t get this problem taken care of soon, then it could lead to a blinking oil pressure light and then eventually wrong readings from the oil pressure gauge.
3) Oil Pressure Gauge Is Wrong
If you have an older vehicle, then it likely has a mechanical oil gauge in it which determines the oil pressure. If the gauge reading shows “0” and yet, your oil levels are completely normal, then it’s likely that your oil pressure sensor is bad.
However, if you’re like most people then you’re driving a modern car made within the last 10-20 years. The oil pressure gauge in a modern vehicle communicates with the oil pressure sensor through an electronic signal.
If you have a bad oil pressure sensor in a modern vehicle, then your oil pressure gauge could show strange readings or it could show that you have extremely high oil pressure or zero oil pressure.
Oil Pressure Sensor Replacement Cost
The good news is that the replacement cost of an oil pressure sending unit is cheap for the average vehicle, costing around $50 for the part alone. The reason being is that it is a simple, inexpensive part and it is easy for mechanics to access in the vehicle.
The labor costs will only be around $100 to $300 depending on how difficult the sensor is to access, and the labor rate of the shop you’re visiting. This means you can expect the total cost of the replacement to run you between $150 and $350.
Costs for some cars including luxury vehicles may be higher. The same can apply when taking your car to a dealership versus an independent mechanic.
Therefore, there is really no excuse for not getting this replacement job done as soon as you notice the symptoms of a bad oil pressure sensor occurring.