OBD-II Code P0523: High Voltage In Engine Oil Pressure Sensor

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Error code P0523 is defined as the Oil Pressure Switch/Sensor High Voltage error. It is a very generic kind of trouble code! It means that this error is a possible breakdown for all vehicles that are equipped with the OBD-II system. This error code is mostly detected in the OBD-II embedded vehicles built after 1996 up to the present. 

This type of error is common in Chevrolet, Dodge, GMC, Mercedes Benz, Cadillac, and even the Pontiac models. The specifications of this error code, symptoms, diagnosis, and repairs might vary depending upon the models of the vehicle. 

P0523 Code Meaning

P0523 Code Meaning

The PCM or Powertrain Control Module, which is also known as the Engine Control Module, is the computer system of the vehicle. It enables multiple controls, sensors, and electronics. One of these evident sensors is the Oil Pressure Sender or Sensor. This sensor aims to detect the amount of mechanical oil pressure within the vehicle engine. 

When the error code P0523 is detected, it indicates that the PCM has stated an extreme value within the engine oil pressure sensor or sender. The sensor works as the 5V circuit, and generally, the code is triggered when the voltage is set at the point of 4.6V or higher than that. This problem is mostly electrical or mechanical. 

OBD-II Code P0523: Symptoms, Causes & Diagnose

Symptoms of P0523 Code

The common symptoms of the P0523 code are somehow similar to that of other error codes that are triggered by the vehicle. But some of them are different and specific to the oil pressure sensor malfunctions. The symptoms include:

  • A high reading in the oil pressure gauge.
  • The Oil pressure indicator lamp will get activated. 
  • The Check Engine light will turn on and register the code onto the memory system of the vehicle. 
  • The PCM might just shut down the engine.
  • Mechanical noises during the operation of the vehicle engine with this fault. 

These are the vital symptoms that you must pay attention to! If you are experiencing any of such hassles, get in touch with your nearest authorized service center. Early detection will help you save your vehicle from further deterioration in internal operations. 

Causes of P0523 Code

Now that you are aware of the symptoms, you need to understand what might trigger this P0523 code. These causes might trigger tons of other problems in the vehicle as well. But P0523 is caused due to one amongst these malfunctions only. The causes include: (P0355 OBD2 Code).

  • Mechanical failures in the oil pump.
  • Clogged or restricted oil passages or oil lines create high pressure that might lead to the problem. 
  • Use of wrong oil for the vehicle engine. 
  • Damaged connectors or cables that lead to the Oil Pressure Sender/Sensor.
  • The OPS sensor might have been damaged. 

How to Diagnose P0523 Code?

How to Diagnose P0523 Code?

Here are the different diagnostic measures that the professionals would take to help detect the root cause of the trigger for the P0523 code:

  • When you take your vehicle to the authorized service center, the mechanic will start the diagnosis aspects. The tool they would prefer to use for the purpose at first is TSB (Technical Service Bulletin) for the specific model and make of the vehicle. 
  • The next diagnostic method is to check the oil level using a dipstick. You need to make sure that the engine is running with the right weight and type of oil. It should not be overdue for the change, should not be 
    too thick, sludged-up, or old. 
  • The mechanics or authorized service professionals will check the wirings and connectors at the oil pressure sending unit. They will look for damage signs such as frayed wires, burnt spots, loose/exposed wirings, etc. They will be using a specific resource to locate the sender. 
  • For some cases, the technicians will also use a mechanical oil pressure gauge to verify the actual oil pressure. They will then compare it to the sensor reading using an advanced scan tool. If the wirings or sensors are faulty, then a mechanical gauge will offer an immediate sign for the same. 
  • If the root cause is still not identified, the sensors will be checked with DVOM. If the sensor doesn’t meet the specifications set by the manufacturer, then it needs a replacement. 

A Common Mistake You Must Avoid

When Diagnosing P0523 Code

The common mistake that the technicians make is that they miss out on checking the voltage that goes into the oil pressure sensor. In most cases, the voltage error is the triggering cause for this code. Therefore, the technicians should use the right tools and expertise to measure the same and check if it is 5V or not. 5V is the specified voltage input that should go into the oil pressure sensor. Anything more or less will disrupt the sensor and might trigger the code! 

How to Fix P0523 Code?

The possible solutions for fixing the P0523 error code are:

How to Fix P0523 Code?

  • Ensure that the oil levels are correct within the engine. Moreover, the oil should also be specifically formulated for the respective engine types. 
  • Fix the system connectors and wiring problems. The worn, loose, and burned wires must be repaired or replaced. 
  • You need to use a particular scan tool to make an oil pressure test. The reading obtained from the test should undergo comparison to that of the value displayed over the OPS Sensor, as per the PCM’s perspective. In case of any inconsistencies, repairs are needed. 
  • Check for the Oil Pressure Sensor to get the reference voltage. If it isn’t, then you should replace the same. 

Tips for Further Avoiding P0523 Code

If the engine light is on and you notice that oil pressure is higher than usual, it indicates a serious problem. There might be an issue with the engine and not just the sensor. So, just changing the sensor should not be the task, but proper diagnosis of the vehicle engine should also be a priority. 


Hence, this is all that you need to know about the P0523 code and its impact on your vehicle. You need to get this fixed within time to ensure that the damage doesn’t deteriorate.