OBD-II Code P0520 — What It Means & How to Fix It

What Does This Error Mean?

P0520 means the engine oil pressure sensor is sending a signal that is out of the normal range. Your engine needs proper oil pressure to stay lubricated and avoid serious damage. This code does not always mean oil pressure is low — the sensor itself may be faulty. But you should treat this seriously until you confirm the actual oil pressure is fine. Do not ignore this code — low oil pressure can destroy an engine quickly.

Affected Models

All vehicles 1996+
Common in GM trucks and SUVs
Common in Dodge and Chrysler vehicles
Common in Ford F-Series trucks
Common in older Jeep models

Common Causes

Faulty oil pressure sensor sending incorrect voltage readings
Low engine oil level causing genuinely low oil pressure
Damaged or corroded wiring to the oil pressure sensor
Clogged oil passages causing actual low oil pressure
Worn oil pump no longer building adequate pressure

How to Fix It

Check your engine oil level immediately using the dipstick with the engine off. If the oil is low, top it off and see if the code clears on its own after a short drive.

Low oil level is the most common cause of real low oil pressure. Always check this first.
Locate the oil pressure sensor — usually on the engine block near the oil filter. Inspect the connector and wiring for corrosion, damage, or loose connections.

Many oil pressure sensors are one-wire sensors on older vehicles. Newer vehicles often have two or three wires.
With the engine running at normal temperature, use an OBD-II scan tool to check the live oil pressure reading. Compare it to the normal range in your repair manual.

Normal oil pressure at idle is typically 10 to 30 PSI. At cruising speed, 30 to 60 PSI is typical.
If the scan tool shows a suspicious reading, install a mechanical oil pressure gauge (available at auto parts stores) to verify actual oil pressure independent of the sensor.

This test tells you definitively whether the pressure is real or just a bad sensor.
If actual oil pressure is fine, replace the oil pressure sensor. If actual oil pressure is genuinely low, take the vehicle to a mechanic immediately — do not drive it.

Running an engine with genuinely low oil pressure even for a few minutes can cause permanent damage.

When to Call a Professional

If you confirm actual low oil pressure, stop driving immediately and call a shop. A bad oil pressure sensor costs $15 to $60 for the part. Labor is $50 to $100 since the sensor is usually easy to access. If low oil pressure is real, repair costs can be much higher — from $300 for an oil pump to $3,000+ for engine damage. Do not delay diagnosis on this code.

Frequently Asked Questions

Is P0520 dangerous?

It can be. If the oil pressure sensor is simply faulty, the car is fine to drive short distances while you get it checked. But if actual oil pressure is low, driving can destroy your engine within minutes. Always check your oil level first, and confirm actual pressure before driving far.

How do I know if the sensor is bad or if oil pressure is actually low?

The best way is to install a mechanical oil pressure gauge. This gives you a reading that does not depend on the electronic sensor. If mechanical pressure is normal but the code is still there, the sensor is bad. If mechanical pressure is also low, you have a real oil pressure problem.

Can I replace the oil pressure sensor myself?

Yes, most oil pressure sensors are easy to replace. You need an oil pressure sensor socket (a special deep socket with a slot for the wire). Drain a little oil first if the sensor is in a spot that will spill. Always check for leaks after starting the engine.