Error P0521 – how to fix?

P0521 OBD-II Error Code: Engine Oil Pressure Sensor / Range / Performance Switch

Diagnostic trouble code (DTC): P0521

P0521 Code Definition

P0521 is defined as an engine oil pressure sensor / range / performance switch failure.

What does the code P0521 mean

All modern vehicles are equipped with a powertrain control module (PCM). This computer controls a number of sensors, controllers and other electronic components. One such sensor is the oil pressure sensor, which detects the mechanical oil pressure in the engine. It then sends this reading to the PCM as a voltage value.

The PCM will notify the driver of this information in two ways. On some vehicles, there is an indicator on the dashboard that shows what the oil pressure is. On other models, there is no indicator, but if there are problems with the oil pressure, the warning light will illuminate.

If the PCM ever detects an unexpected value, code P0521 is stored. The unexpected value may simply be greater or less than the allowable range, or the pressure may simply be constant in place while it should be fluctuating.

What causes the code P0521?

The most common causes of the P0521 code are

• Open or shorted lines in the circuit of the oil pressure send module.
• Mechanical engine failure
• Incorrect oil pressure
• However, the most common cause of this fault code is the lack of sufficient engine maintenance by the owner. Failure to regularly change the oil can eventually lead to a low oil pressure / level condition. Most engines use at least one quart of oil every 3,000 miles. At this point, you need more.

What are the symptoms of the P0521 code?

As mentioned above, this problem is usually accompanied by a dashboard alert in two ways. The mechanic working on the car may also notice that the correct codes have been saved. These would be:

If the oil level in the vehicle is too low but the driver does not know it because he is not getting an accurate reading. Another symptom may be simply loud noises coming from the engine. Failure to do so may result in engine failure.

How can a mechanic diagnose the P0521 code?

The P0521 diagnostics will begin with the mechanic using an OBD-II scanner to extract all the codes that the PCM has stored. If the warning light on the dashboard is on, this will also assist the technician in making a diagnosis.

To confirm what the vehicle’s information mechanisms say, the mechanic will open the hood and check the oil level. If the oil appears to be fine, it will clear the PCM codes and reset the vehicle to see if these codes reappear. If so, then PCM is the culprit.

The most common errors when diagnosing the P0521 code

The oil pressure sensor may need to be replaced, but should not be done by a mechanic until a complete inspection has been performed. While this may clear the code and make the dashboard light go away, the engine may already be faulty. Without checking it, the mechanic will send your client back on the road with a big problem under the hood.

How serious is the P0521 code?

If detected early and fixed immediately, this code doesn’t have to worry anyone. However, if the driver tries to postpone this, the engine may be seriously damaged. Repair will be very costly to say the least. In the worst case scenario, the engine can fail completely, which is a very costly problem.

What repairs can remove the P0521 code?

In many cases it is enough to change the oil and / or reset the oil pressure sensor. The engine itself may require major repairs.

Additional notes regarding the P0521 code

This should be a good reminder to owners that their vehicles require an oil change every 3,000 miles. Postponing it may not seem like a big deal, but it can quickly become one.