Volkswagen Jetta P0520: Oil Pressure Switch/Sensor → Circuit

The OBD2 code P0520 can be used to indicate trouble.  It’s generic, which means that it has the same meaning for the Volkswagen Jetta as it would any other vehicle.  P0520 indicates that the oil pressure sensor is operating outside of its normal “range”.  It's usually due to a problem with the wiring or an oil pressure sensor switch.

Your Jetta’s oil pressure sensor measures the oil pressure mechanically, and converts that reading into a voltage signal that the ECM (Computer) converts into an oil pressure reading.  This is the signal that triggers your oil warning light and appears on your oil pressure gauge.

Red oil alert lights are a sign of a problem.  Don't assume the oil pressure sensor has failed.  If there's no oil pressure, then P0520 could occur.

P0520 Quick facts

• Oil pressure sensors are the most frequent cause.
• You can also get it from low oil pressure.
• If you hear knocking or have the low oil pressure light, don’t drive until P0520 is diagnosed.
• P0521.

P0520 Symptoms:  Volkswagen Jetta

Other than the check-engine light, there are rarely any other symptoms.  The oil pressure may be low if the engine is making unusual noises (clacky, metallic), 

P0520 Causes:  Volkswagen Jetta

• Oil Pressure Sensor It is possible that P0520 was caused by an oil pressure sensor. However, it would be prudent to inspect the oil level and quality as well as the wiring before assuming any responsibility.
• Oil Pressure Sensor Wiring - The signal from the oil pressure sensor is P0520. This indicates that there has been a malfunction in the circuit.  It could be a problem with the wiring.
• You can have low or no oil The first thing that you should do is check to see if there is oil in your vehicle’s engine at all.  The crankcase can give P0520 if the oil level is very low.  Clear the code, then fill up the oil and fix it.  
• Low Oil Pressure This code will be displayed if the oil pressure is too low.  The oil light should indicate that it is present, as well as a reading of low oil pressure from the gauge. 
• Wrong oil or dirt? If your Jetta’s oil hasn’t been changed for a long enough period of time, it can interfere with the oil pressure sensor, even if there still is oil pressure.

Jetta P0520 Diagnosis

Below are steps to help a mechanic diagnose the P0520 problem in your Volkswagen Jetta.  

1. Examine the oil

Check the oil level first.  If it’s full make sure that it looks healthy.  It may have a problem with the oil pressure sensor if it is darkened or stained.  If the vehicle is past it’s oil change deadline (regardless of how the oil looks), changing the oil would be a good idea.

2. Check the Wiring Harness

Next, you should inspect the wiring harness running from the oil pressure sensor to the ECM.  It could also be the cause of P0520.  Don’t forget to make sure that the harness is still plugged into the sending unit and undamaged.  

This code can be thrown for many reasons, including wiring issues.  The wiring is close to the Jetta’s exhaust and can get brittle over time.

3. Check the Oil Pressure Manually

After confirming that both the oil level, and the wiring are fine, it is time to check the oil pressure manually.  There are two options: Manual oil pressure gauge to see if it’s where it needs to be.  These are simple to use.  Here’s a Amazing YouTube video That will explain exactly how to use the gauge for checking.

If the oil pressure from the gauge reads ok, you’ll need to replace the oil pressure sending unit/sensor.  If there is low or no oil pressure, you’ll need to figure out why.

Conclusion:  P0520 Volkswagen Jetta

The process of diagnosing P0520 can be done easily.  If your oil light is on, ensure that oil pressure has been checked.  Good luck fixing your Jetta!