Explaining the symptoms of a bad pressure sensor in a bit of detail:
1. Check Engine Light
If anything goes wrong with any sensor, relay, or switch in the car, the check engine light will come on. It is the first and foremost indication that some electronic components of your vehicle have gone bad.
This is the same with an oil pressure sensor. When it goes out, your car’s ECU is informed about this immediately. It will stop receiving readings from the pressure sensor. In some cars a failed oil pressure sensor can cause the Check Engine light to come on with the code P0520 – Engine Oil Pressure Sensor Circuit.
2. Oil Pressure Warning Light
Apart from the check engine light, there is a separate oil pressure light on the dashboard panel. It is directly connected to the oil pressure sensor. Your car’s oil pressure gauge will give a good indication of the overall oil levels in the engine. In case the Low oil light comes on, and you check the oil and find its okay, then you certainly have a faulty oil pressure sensor. When the oil pressure sensor is defective, it will give inaccurate readings. The quicker you replace the sensor, the less stress you will have to check your oil levels in your vehicle.
3. Sporadically Blinking Oil Light
When your oil pressure sensor is about to fail, the Low Oil light will blink on and off. This can be quite frightening to a car owner since low oil could cause significant damage to an engine. When the engine oil pressure sensor goes bad, you may get faulty readings on the oil pressure gauge. If the oil pressure reading is too low or high, the engine’s oil pressure light comes on.
But when you start seeing a blinking oil pressure light, it means that the oil pressure may have crossed the allowable pressure limits on either extreme by a considerable margin. Thus, you need to check your car immediately if the oil pressure warning light starts blinking.
4. Strange Noises from Engine
During each revolution of an engine cycle which is a combination of different rotary parts in the combustion chamber, surfaces of parts like bearing and camshafts touch each other.
A faulty pressure sensor might send a high oil pressure reading to the ECU when the actual oil pressure is low. The ECU will instruct the oil pump to lower the oil pressure in this scenario. As a result, the oil pressure drops to even lower levels. The engine oil will not reach some locations due to this. Hence the metallic surfaces will mate with each other under dry conditions. There will be clinking noise coming out of the engine. Clinking noise from the engine is a clear indication that something has gone wrong with a vehicle’s lubrication system.
5. Faulty Oil Pressure Gauge Readings
An oil pressure gauge receives readings from the oil pressure sensor. When the oil pressure sensor goes bad, it starts reading the wrong internal pressure in the oil pressure sending unit. Consequently, faulty reading is displayed on the oil pressure gauge as well.
On an older car, it could likely have a mechanical gauge monitoring oil level. When the oil levels are normal but your gauge is pointing at zero, it could mean that the oil pressure sensor needs to be replaced because it is giving inaccurate readings. It could also be a sign of a connection problem.
On a modern car, an oil pressure gauge uses an electronic signal to get a reading, when the oil pressure sensor is bad, it will throw off strange readings. It could either sit at full or zero. It is advisable to check the sensor wiring or replace the sensor as needed.
You mustn’t assume your engine oil level is low without physically confirming with a dipstick. Otherwise, it could mean having too much engine oil in your car, which could set off an entirely new set of issues.