Dodge Dart P0521: Oil Pressure Sensor Switch → Performance/Range

P0521 This is an OBD2 diagnostic Code that is activated when you Dodge Dart The oil pressure sensor detects an error and sends a message to inform the user that it is outside its normal operating range.

It's usually due to a problem with your oil system or a bad oil pressure sensor. This should be addressed immediately.  It is possible, and even probable that an oil pressure sensor/sensor is defective. However, it could also indicate a problem in the oil pressure.  

Your Dart’s oil pressure sensor measures the oil pressure mechanically, and converts that reading into a voltage signal that the PCM (Powertrain Control Module) converts into an oil pressure reading.  The oil warning light is activated when this reading appears on the oil pressure gauge.

P0521 Quick facts

• Most often caused by an issue with your Dart’s oil pressure sensor or circuit
• You should take P0521 very seriously
• Most common symptoms are the oil light and an incorrect oil pressure gauge reading.
• It is easy to diagnose

P0521 Symptoms:  Dodge Dart

Below are some symptoms common to P0521.

• Glow-Low Oil/Gauge The most common cause of P0521 is a poor oil pressure sensor. However, the readings from an oil pressure gauge and low-oil warning should be treated as correct until you are certain.
• Ticking or Knocking - If your engine is ticking and knocking, it’s likely that the oil pressure sensor is accurate and there’s a problem with the engine or you need oil.
• Check Engine Light– That’s why you are here.

Dart P0521 Causes

The problem with your sensor wire or sensor sensor is what causes P0521. This would indicate that your engine is in good condition.  Or it is going to be caused by an issue your Dart’s oil level, viscosity, pressure, or cleanliness.  

Proper oil flow is vital to an engine's performance. This code must be respected and followed.

Below are the top causes of P0521.

• You can have low or no oil The first thing that you should do is check to see if there is oil in your Dart’s engine at all.  The crankcase can give P0521 when it is low or empty.  Clear the code and fill up the oil.  
• Low Oil Pressure The code will appear if oil pressure drops too low.  This code should be accompanied by the oil light or low oil pressure readings from the oil gauge.  Diagnose Low Oil Pressure in Dodge Dart
• Wrong or dirty oil- If there hasn’t been an oil change for a long enough period of time, it can interfere with the oil pressure sensor, even if there still is oil pressure. 
• Oil Pressure Sensor Wiring - P0521 means that the signal coming from the oil pressure sensors is not within the range.  It indicates that the wiring is not working properly.
• Oil Pressure Sensor It is possible that the problem may be caused by an oil pressure sensor. However, it's smart to first look at the oil and wiring.

Diagnose P0521: Dodge Dart

This P0521 diagnosis order is written (like everything on the site) for the DIY guy who doesn’t have a lot of specialty tools. 

1. Take a look at the oil

Check the oil level first.  If it’s full make sure that it looks healthy.  It may interfere with your oil pressure sensor if it is blackened or gritty.

2. Examine the Wiring Harness

Next, you should inspect the wiring harness running from the oil pressure sensor to the PCM.  You could have P0521 if the wiring is damaged.  Don’t forget to make sure that the harness is still plugged into the sending unit and undamaged.  

This code can be thrown for many reasons, including wiring issues.  The wiring is close to the Dart’s exhaust and can get brittle over time.

3. Manually check your oil pressure

After confirming that both the wire and the oil level are good, it is time to check the oil pressure manually.  There are two options: Oil pressure can be manually adjusted gauge to see if it’s where it needs to be.  These are simple to use.  Here’s a Amazing YouTube video This will demonstrate how you can use the gauge to test.

If the oil pressure from the gauge reads ok, you’ll need to replace the oil pressure sending unit/sensor.  They’re cheap.  If there is low or no oil pressure, you’ll need to figure out why.

Conclusion

It’s relatively straightforward diagnosing P0521.  This is made easier by knowing the exact oil pressure.  If you have any suggestions, please leave them below. Good luck with your Dodge Dart.