P0520 indicates a fault with the oil pressure sensor circuit. UK repair costs, causes and fixes for OBD2 fault code P0520.
This page explains the code in plain English and gives indicative UK repair and MOT context. It does not confirm the exact failed part. Vehicle age, engine, related codes, live data, and workshop inspection can all change the final diagnosis and quote.
P0520 indicates a fault with the oil pressure sensor circuit. UK repair costs, causes and fixes for OBD2 fault code P0520. When this fault is detected, the ECU (Engine Control Unit) stores the code and usually illuminates the check engine light on the dashboard.
In practice, P0520 should be treated as a general powertrain diagnostics problem first, not as proof that one named part has failed. The value of the code is in narrowing the system, checking related data, and avoiding the usual misdiagnosis before parts are ordered.
The primary symptom is an illuminated check engine light (malfunction indicator lamp) on your dashboard. Depending on the severity of the fault, you may also experience rough running, reduced fuel economy, or changes in engine performance. Some vehicles show no drivability symptoms at all — the warning light may be the only indication of a problem.
Fault code P0520 is triggered when the vehicle's ECU detects a reading or performance level outside the expected range for that system. P0520 indicates a fault with the oil pressure sensor circuit. UK repair costs, causes and fixes for OBD2 fault code P0520. Common causes include sensor failure, wiring faults, mechanical issues, or secondary faults caused by another problem elsewhere in the vehicle. A full diagnostic scan should always be carried out to check for related fault codes before any parts are replaced.
The repair approach for P0520 depends entirely on the root cause identified during diagnosis. Always start by scanning for any related fault codes that might indicate the primary fault. Check wiring and connectors before replacing sensors or components. If the fault is sensor-related, replacement is usually straightforward. If the fault indicates a mechanical issue, a qualified mechanic should assess the vehicle before any work is carried out. After any repair, clear the code and road test to confirm the fix.
The typical UK cost to diagnose and repair fault code P0520 ranges from £30 to £200 including parts and labour at average UK workshop rates, including VAT. Costs vary significantly by vehicle make and model, and by region. Independent garages are typically 30–50% cheaper than franchised main dealers. Always get at least two quotes, and ask the garage to confirm the fault cause before authorising any repair.
P0520 is most likely part of the Engine Oil Pressure Sensor/Switch Circuit Malfunction diagnostic family, which means the code identifies a monitored system but not always the exact failed part. On UK cars the right approach is to confirm live data, wiring integrity, and related faults before replacing components.
The main risk with P0520 is treating the code description as a final diagnosis. Fault codes point to a system or behavior, not always the exact failed component.
Fault code P0520 does not directly cause an automatic MOT failure, but an illuminated check engine light (MIL) is an automatic MOT failure under DVSA rules. If the warning light is on when you arrive for your test, the vehicle will fail. Get this fault diagnosed and the light cleared before your MOT appointment.
Even if the light is not currently on, if the fault is intermittent it could reappear during the test. Use our AI Diagnostic Report to understand the MOT risk specific to your vehicle and get advice on whether it is safe to proceed to your test.
Specific to your vehicle — year, make, model and engine.
Includes step-by-step repair guide, exact UK labour costs and MOT impact.
Can I drive with fault code P0520?
Check your oil level immediately. If oil level is fine it may be a faulty sensor — but never ignore a low oil pressure warning.
Will P0520 clear itself?
Some fault codes will clear automatically after the underlying issue resolves itself, but P0520 typically stays stored until the fault is fixed and the code is manually cleared with an OBD-II scanner. Do not assume the problem has gone away if the light turns off temporarily.
Do I need a garage or can I fix P0520 myself?
Whether P0520 can be fixed at home depends on the root cause. Sensor replacements are often achievable for confident home mechanics. Mechanical or electrical faults usually require specialist tools and knowledge. Always get a full diagnosis before attempting any repair.
How much does it cost to fix P0520 in the UK?
UK repair costs for P0520 typically range from £30 to £200 depending on your vehicle, the root cause, and your local garage rates. Use our AI Diagnostic Report for a cost estimate specific to your car.
These fault codes are commonly found alongside P0520 or share similar causes:
Last updated: June 2026. AI-Diagnostics-Pro provides AI-generated information for educational purposes only. It is not a substitute for professional automotive advice. Always consult a qualified mechanic before carrying out vehicle repairs. Repair cost estimates are approximate and may vary by region and vehicle.
