P0520 Code: Meaning, Symptoms, Causes & Fix

Overview

Code P0520 indicates a fault in Engine Oil Pressure Sensor/Switch Circuit Malfunction, typically within powertrain controls.

Symptoms

rough operation in certain conditions
check engine light
increased fuel use

Common causes

Broken terminal inside harness affecting engine oil pressure sensor/switch circuit malfunction
Disconnected or loose connector
Connector pin damage/corrosion or harness stress near related components

How to diagnose P0520

Confirm P0520 and capture freeze-frame data with a professional scan tool.
Inspect wiring, connectors, and grounds related to engine oil pressure sensor/switch circuit malfunction for obvious defects.
Use a continuity test from module pin to component to identify opens/high resistance.
Check for related DTCs to identify the root-cause chain before replacing parts.
After repair, clear codes and confirm readiness monitors complete without recurrence.

Severity of code P0520

High: This code is high severity because the affected system can directly impact drivability, safety, or catalyst/engine protection.

Can you drive with P0520?

Driving with P0520 should be limited to a short trip for diagnosis/repair. Continued driving can cause expensive secondary damage.

If the warning lamp is flashing or drivability/safety is affected, avoid driving and diagnose immediately.

How to fix it (step-by-step)

Repair obvious wiring/connector faults first to prevent repeat parts replacement.
Address the root fault mode (open) in the engine oil pressure sensor/switch circuit malfunction circuit/system.
Apply the required relearn/adaptation procedure if specified by service information.
Road-test and verify P0520 remains cleared under the conditions that originally set the code.

Fix options

Clear corrosion and protect terminals.
Repair open circuit and secure connector lock.
Clear DTCs and verify with live data and completed drive cycle.

Typical repair cost

$400-$2000

Common mistakes when diagnosing P0520

Replacing parts without verifying voltage, ground, and signal integrity first.
Ignoring related stored/pending codes that indicate upstream faults.
Skipping post-repair verification drive cycle and readiness checks.

P0520 in common vehicles

P0520 appears across makes such as BMW, Mercedes-Benz, Audi, Volvo. Failure patterns differ by platform: wiring routes, software calibration, and component supplier revisions can change root cause.

Frequently asked questions

What causes P0520?

P0520 is commonly set by open faults affecting engine oil pressure sensor/switch circuit malfunction.

How much does it cost to fix P0520?

For P0520, repair costs are typically $400-$2000 depending on exact root cause, labor rates, and part quality.

Can I clear P0520 without repair?

You can clear P0520 temporarily, but the code usually returns until the underlying fault is corrected.