One component that many motorists tend to forget is the engine oil pressure sensor. Although the Oil Pressure Sensor (OPS) is a relatively simple part, it can trigger a series of anxiety-inducing warnings on your dashboard when it fails. Keep reading the common failures of an oil pressure sensor , and you will know when it is defective.
If you’re experiencing one or more symptoms associated with a bad oil pressure sensor, you’ll want to address the issue immediately.
What is the function of the oil pressure sensor?
The oil pressure sensor (also known as an oil pressure sending unit) is a pressure transducer that measures engine oil pressure . As the engine oil pressure changes, so does the internal resistance of the sensor.
Most older vehicles have the oil pressure sensor connected directly to the oil pressure gauge. Normally, one side of the gauge receives battery power, while the OPS provides a ground on the other side. As the OPS changes its internal resistance in response to oil pressure, the pressure gauge is forced to move.
The operation of the oil pressure sensor is a little different on many late model vehicles. In a typical system, the engine computer (often referred to as the powertrain control module (PCM)) receives information from the oil pressure sensor. The module then transmits that information to the instrument cluster, which, in turn, operates the oil pressure gauge or warning light as needed.
If the PCM detects a problem with the oil pressure sensor or its circuit, it will turn on the check engine light and store a diagnostic trouble code in memory .
Some vehicles have an oil pressure switch in addition to or instead of the oil pressure sensor. The switch closes when the oil pressure drops below a certain threshold. Closing the switch causes the low oil pressure light on the instrument panel to come on.
The terms oil pressure sensor and oil pressure switch are often used interchangeably.
Symptoms and common failures of a damaged oil pressure sensor
Oil pressure sensors are designed to last the life of the vehicle, but that’s not always the case. Like any other auto part, your car’s oil pressure sensor can go bad eventually, leading to some truly notable common oil pressure sensor symptoms and failures.
1- Incorrect oil pressure gauge reading
If your car is equipped with an oil pressure gauge, a faulty oil pressure sensor will almost always cause the gauge to read incorrectly. You may notice that the gauge needle is stuck at one end of its sweep or that the gauge works intermittently.
2- Oil pressure warning light is on
A faulty oil pressure sensor or oil pressure switch can falsely signal a low oil pressure condition, causing the oil pressure warning light to come on. This is a very common failure of an oil pressure sensor.
3- Engine light illuminates
In many modern vehicles, a computer, known as a control module, monitors the OPS. If the module detects a problem with the OPS, it will turn on the check engine light and store a diagnostic trouble code in memory.
(A loss of engine oil pressure can cause many of the same symptoms as a faulty oil pressure sensor. Running an engine with low oil pressure can quickly cause serious internal damage . You should immediately shut down the engine if engine warnings dashboard indicate low oil pressure)
What happens if the oil pressure sensor fails and I drive?
You should never assume that the oil pressure sensor is to blame for a low oil pressure warning on the dash. The problem could be an actual loss of oil pressure within the engine.
Therefore, to minimize the chance of costly internal engine damage, you should shut down your car immediately when a low oil pressure warning appears on the dash. Then have the vehicle towed to your destination of choice for diagnosis.
If you (or your mechanic) determine that the vehicle has a faulty OPS, you should fix the problem immediately. Without a working oil pressure sensor, you’ll have no way of knowing if your engine’s oil pressure becomes dangerously low .