Engine Oil Pressure Sensor/Switch Circuit
What does P0520 mean?
The P0520 code means the vehicle's onboard diagnostic system has detected: Engine Oil Pressure Sensor/Switch Circuit. This is a critical severity code.
Common Symptoms
- Oil pressure warning light on dash
- Oil pressure gauge reading abnormally
- No oil pressure indication at all
- Engine ticking or knocking noise
- Check engine light on
Probable Causes (Ranked by Likelihood)
- Faulty oil pressure sensor/switch Very High
- Wiring or connector issue to oil pressure sensor High
- Actually low oil pressure due to low oil level High
- Oil pressure sensor circuit open or shorted Moderate
- PCM fault reading oil pressure signal Low
Step-by-Step Diagnostic Procedure
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Check engine oil level and condition first -- top off if low
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Install a mechanical oil pressure gauge to verify actual oil pressure (should be 25-65 PSI at operating temp)
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Inspect oil pressure sensor connector for corrosion, oil contamination, or loose fit
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Measure oil pressure sensor resistance -- compare to manufacturer specifications
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Check wiring continuity from oil pressure sensor to PCM
Frequently Asked Questions
Can I drive with code P0520?
Do not drive until you verify actual oil pressure with a mechanical gauge. If the sensor is simply faulty and real oil pressure is normal, you can drive. But if actual oil pressure is low, driving can destroy the engine in minutes.
How do I know if it is the sensor or actual low oil pressure?
Install a mechanical oil pressure gauge in place of the sensor. If the mechanical gauge shows normal pressure (25-65 PSI at operating temperature), the sensor is faulty. If pressure is low, you have a real oil pressure problem that needs immediate attention.
Where is the oil pressure sensor located?
The oil pressure sensor is typically located near the oil filter housing on the engine block. On GM LS engines, it is at the back of the block near the distributor location. On many 4-cylinder engines, it is near the oil filter on the front or side of the block.