Oil pressure sensors

The most common sign of a sensor issue is the activation of the oil pressure indicator light on the dashboard. If the sensor is not working properly, it can send false information to the ECU, triggering the warning even if the oil pressure is normal. An oil pressure indicator light which either flashes or comes on and goes out randomly may also indicate a faulty sensor or faulty electrical connections. If the vehicle is fitted with an oil pressure gauge (in addition to the indicator light), you may notice that the reading is consistently too low or too high, or that it fluctuates abnormally. An incorrect reading is often the result of a faulty sensor which is not measuring the pressure correctly. In some cases, failure of the oil pressure sensor can lead to engine stalling or loss of power. This occurs when the engine control unit (ECU) receives incorrect information from the sensor, resulting in inappropriate actions, such as limiting engine performance to prevent potential damage. If the oil pressure sensor is faulty and is transmitting false information, it may not properly warn the driver in the event of a genuine drop in the oil pressure. In this case, the engine may lack lubrication, resulting in mechanical noises such as rattling or squeaking coming from the engine’s internal parts. A faulty sensor can sometimes cause a false alarm indicating a lack of oil, even if the level is correct. This can lead the driver to unnecessarily add oil, resulting in excessive oil consumption. In some cases, a faulty oil pressure sensor can affect the entire operation of the engine. The engine management system may enter “safe” mode or limit performance to protect the engine against potential damage.

Firstly, we strongly recommend that you check the oil level and quality. A low oil level can cause an actual drop in the oil pressure, triggering the sensor. Degraded, old, or poor-quality oil can also affect engine lubrication and cause incorrect pressure readings.

You can also visually inspect the various components of the oil pressure sensor (wires and connectors), to determine whether there are any visible faults.

Secondly, if possible, we recommend that you test the sensor with a multimeter. Depending on the type of sensor, the resistance between the terminals of the sensor should vary along with the pressure, but it is necessary to refer to the manufacturer’s specifications for the correct values. Some sensors generate a voltage signal which is proportional to the oil pressure. It is important to test the voltage output using a multimeter in direct voltage (DC) mode to check whether the sensor output varies when the engine is running.

If this is not sufficient, we advise that you go to a professional, so that they can use an OBD-II diagnostic tool to identify the fault codes associated with the oil pressure sensor.  For example, codes such as P0520 or P0523 may indicate issues with the sensor in question. These codes may indicate a faulty sensor, abnormal pressure, or another issue related to engine oil management.

If the preceding tests are inconclusive, then you will need to replace vehicle’s oil pressure sensor.

Like any electronic or mechanical component, the oil pressure sensor wears out over time. Sensors exposed to harsh operating conditions, such as extreme temperatures and constant vibration, can wear out more quickly. Engine oil may contain contaminants, such as metal particles, dirt, or residue from used oil. These contaminants can obstruct the sensor or clog up its internal components. Oil may leak around the sensor if the gaskets or connections are worn or damaged. This can also affect the sensor’s internal components. The electrical cables connecting the sensor to the engine management system may be damaged by wear, corrosion, or short circuits. Loose or incorrectly fixed connections can also prevent the sensor from transmitting accurate data. If the oil pump is not working properly, this directly affects the oil pressure in the engine. An operational sensor may therefore correctly indicate abnormal pressure, but in this case, it is not the sensor which is at fault. However, prolonged malfunction of the pump can also damage the sensor due to poor oil circulation. The oil pressure sensor is exposed to high temperatures under the hood. If the engine regularly overheats, or if the sensor is positioned near to very hot areas, internal electronic components may be damaged. A damaged or worn gasket can allow oil to enter the sensor’s electronic components. This can lead to short circuits or incorrect pressure readings. Using engine oil that is not recommended for the vehicle, or poor-quality oil, can affect the oil pressure and, consequently, the reading from the sensor. Oil that is too thick or too thin can cause abnormal pressure fluctuations. Like any electronic component, some sensors may be faulty when they leave the factory. Design faults or poor-quality materials can cause premature failure. Over time, vibrations generated by the engine or uneven road surfaces can cause the sensor to fail, especially if it is incorrectly fixed or directly exposed to these vibrations. This may affect the sensor’s internal components or cause electrical disconnections. an issue in the oil pressure regulation system, such as a faulty or jammed pressure regulator, may affect the reading from the sensor. Even if the sensor itself is working properly, a regulator that is not working properly could result in incorrect oil pressure readings.

We recommend that you follow the steps below to replace your oil pressure sensor as efficiently as possible and to minimize the risk of any error:

1. 1. Disconnect the vehicle battery’s negative terminal.
   2. Locate the oil pressure sensor, which is usually located near the oil pump or the oil filter, or on the engine block.
   3. Carefully disconnect the electrical connector from the sensor.
   4. Using a suitable socket wrench, remove the sensor by turning it anticlockwise.
   5. Clean the fitting area with a clean cloth or cleaning fluid to remove any excess oil, dirt, or residue.
   6. Apply a sealing product (optional). Some sensors require a sealing product (usually Teflon tape) to be applied to the threads to ensure correct sealing. Refer to the sensor’s instruction manual to find out whether this is necessary.
   7. Start screwing in the new sensor by hand to avoid crossing the threads.
   8. Then tighten with a torque wrench, in accordance with the manufacturer’s recommendations. Depending on the model of the sensor, the tightening torque will be between 10 Nm and 20 Nm.
   9. Reconnect the electrical connection and, if necessary, apply dielectric grease to the connector to protect it against corrosion or moisture.
   10. Reconnect the vehicle’s battery.
   11. Check for any oil leaks around the sensor.
   12. Using the OBD-II tool, reinitialize any error codes that may be linked to the sensor.

As the oil pressure sensor is essential to the correct operation of the engine, it is important to follow certain advice to prolong its service life:

• Apply a good sealing product (Teflon tape or liquid gasket);
• Use a torque wrench to comply with the recommended tightening torque (between 10 Nm and 20 Nm for this type of sensor);
• Always replace the gasket, otherwise there is a risk of leakage.