P0521 OBD-II error code: engine oil pressure sensor/range switch/performance switch.
Diagnostic Trouble Code (DTC): P0521
P0521 Code Definition.
Code P0521 is defined as engine oil pressure sensor/range/capacity switch failure.
What does the P0521 code 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 of these sensors is the oil pressure sensor, which detects the mechanical pressure of the oil in the engine. It then sends this reading to the PCM in the form of 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 a warning light comes on if there is an oil pressure problem.
If the PCM ever detects an unexpected value, code P0521 is recorded. The unexpected value may simply be higher or lower than the allowable range, or the pressure may simply be constant in place while it should be fluctuating.
What causes code P0521 to occur?
The most common causes of the P0521 code are as follows.
- Open or shorted wires in the oil pressure sending module circuit.
- Mechanical engine failure
- Incorrect oil pressure
- However, the most common cause of this fault code is the owner’s failure to sufficiently maintain the engine. Failure to change the oil regularly can eventually lead to a low oil pressure/level condition. Most engines use at least a quart of oil every 3,000 miles. At this point, more is needed.
What are the symptoms of code P0521?
As mentioned above, this problem is usually accompanied by a warning on the instrument panel in two ways. A mechanic working on the car may also notice that corresponding codes have been recorded. These would be:
- P0520
- P0522
- P0523
- P0524
If the oil level in the vehicle is too low, but the driver doesn’t know it because he doesn’t get an accurate reading. Another symptom may simply be loud sounds coming from the engine. Otherwise, the engine may fail.
How can a mechanic diagnose code P0521?
The P0521 diagnosis will start with the mechanic using an OBD-II scanner to extract all the codes that the PCM has stored. If the warning light on the instrument panel is on, this will also help the technician make a diagnosis.
To confirm what the vehicle’s reporting mechanisms say, the mechanic will open the hood and check the oil level. If the oil seems fine, he will clear the PCM codes and restart the vehicle to see if the codes reappear. If so, the PCM is the culprit.
The most common errors when diagnosing the P0521 code.
The oil pressure sensor may need to be replaced, but the mechanic should not do this before performing a thorough check. While this may clear the code and make the dashboard light go away, the engine may already be damaged. If you don’t check this, your customer will be back on the road with a big problem under the hood.
How serious is code P0521?
If detected early and dealt with immediately, this code need not worry anyone. However, if the driver tries to delay this action, it could lead to serious engine damage. At the very least, it will be very expensive to repair. At worst, the engine may fail completely, which is a very expensive problem.
What repairs can clear code P0521?
In many cases, changing the oil and/or resetting the oil pressure sensor is sufficient. The engine itself may require major repairs.
Additional notes on code P0521
This should be a good reminder to owners that their vehicles need an oil change every 3,000 miles. Your suspension may not seem like a big deal, but it can quickly become one.
