What does code P0520 mean?

P0520 means the oil pressure sensor's signal is electrically implausible. It’s moderately serious — you can usually keep driving gently, but diagnose it soon.

My oil light flickers at idle but the engine sounds fine. Sensor?

Maybe — or marginal pressure from a worn pump/bearings showing up exactly where pressure is lowest (hot idle). This precise symptom is why the mechanical-gauge test exists. Do it before dismissing the light.

Can I drive to the shop?

With a LOW pressure reading: ideally no — tow it or verify with a gauge first. With a stuck-high/circuit code and a quiet engine: short careful drives are reasonable while you arrange the fix.

P0520 — Engine Oil Pressure Sensor Circuit

Moderate

Quick answer

P0520 means the oil pressure sensor's signal is electrically implausible. First move: check the connector at the sensor (oil-soaked connectors are routine here), then test the sensor — but never assume: verify real pressure with a mechanical gauge if there's any doubt.

What it means

P0520 reports that the oil pressure sensor's signal is electrically implausible.

Oil pressure is the engine's blood pressure, and this sensor is the only witness the dashboard has. The golden rule: treat low-pressure readings as TRUE until a mechanical gauge proves the sensor lied. The cost of believing a lying sensor is a new sensor; the cost of ignoring a truthful one is a new engine.

Like every code on this site, the diagnosis below runs cheapest-first — the order exists because the cheap causes really are the common ones.

P0520 symptoms: what you'll notice

Oil pressure gauge reading erratically — pegged high, dropped to zero, or jumping around
Oil pressure warning light flickering or on, often while the engine sounds completely normal
Check engine light, frequently the only thing you notice
No change in how the car drives — this is a signal-circuit code, but verify real pressure before relaxing

Common causes

Ordered from most to least likely.

1.

See the diagnosis steps

This family shares its suspect list; the steps below walk it in order of cost and likelihood.
2.

Wiring or connector damage

The universal suspect for any circuit-flavored code.
3.

The component named by the code

Condemned by measurement, never by guess.

How to fix it: diagnosis, step by step

Cheapest and most likely checks first.

1 Check the oil level right now

Before any electrical theory: dipstick. Low oil causes genuinely low pressure, and that's an emergency the sensor is correctly reporting.
2 Listen to the engine

Ticking or knocking that wasn't there before, especially at idle when hot, supports a REAL pressure problem. A quiet, normal engine with a dramatic reading leans toward the sensor — but verify, don't assume.
3 Verify with a mechanical gauge

Thread a mechanical gauge into the sensor's port (adapters are cheap; many parts stores rent the kit). Real pressure at spec = replace the sensor and drive happy. Real pressure low = stop running the engine and diagnose (pump, pickup screen, bearings).
4 Inspect the sensor's circuit

Connector corrosion and oil wicking into the harness are routine at this sensor's location. An oil-filled connector both fails electrically and leaks — fix the leak too.

Parts & tools you may need

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Frequently asked questions

What does code P0520 mean?: P0520 means the oil pressure sensor's signal is electrically implausible. It’s moderately serious — you can usually keep driving gently, but diagnose it soon.
What does P0520 mean in plain words?: The oil pressure sensor's signal is electrically implausible. Check the connector at the sensor (oil-soaked connectors are routine here), then test the sensor — but never assume: verify real pressure with a mechanical gauge if there's any doubt.
My oil light flickers at idle but the engine sounds fine. Sensor?: Maybe — or marginal pressure from a worn pump/bearings showing up exactly where pressure is lowest (hot idle). This precise symptom is why the mechanical-gauge test exists. Do it before dismissing the light.
Can I drive to the shop?: With a LOW pressure reading: ideally no — tow it or verify with a gauge first. With a stuck-high/circuit code and a quiet engine: short careful drives are reasonable while you arrange the fix.