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P0523 Code – What Does It Mean & How To Fix It

This is one of the most frequent OBD2 trouble codes. Read the full article below to know what it means, how to fix it, and what other codes may show related to it.


P0523 is an OBD-II Code that refers to Engine Oil Pressure Sensor/Switch High Input


A P0523 code is caused by an ECM (Engine Control Module) receiving a signal that the Powertrain Control Module has found that the engine oil pressure sender/sensor is too high. The source of the problem is most likely either mechanical or electrical. The majority of the time, the difficulties are electrical in nature.


Common causes for this code include:

  • High pressure as a result of a blockage or restriction in the oil flow path
  • Incorrect engine oil was used
  • Oil pressure sender failure due to a defective connection or faulty wiring
  • Faulty Engine Oil Pressure Sensor/Sensor
  • Not changing the oil at regular intervals

Also Read: What Causes High Oil Pressure


The symptoms of a P0523 code are:

A trouble code is stored and the MIL (Malfunction Indicator Lamp) is illuminated

The engine oil pressure will be extremely high

Engine performance issues (i.e. the vehicle may not start or it may idle roughly)

Possible catastrophic engine failure


To diagnose a P0523 DTC code, a technician would:

  1. Use a scan tool to view the freeze frame data
  2. Perform an inspection of the engine oil pressure sender/sensor using a test light
  3. Check for proper voltage at the powertrain control module harness connector terminals
  4. Check for interruptions in the signal wire between the ECM and oil pressure sensor/switch assembly

Common mistakes

The following are common mistakes when diagnosing the trouble code P0523:

Using a digital multimeter to test the oil pressure sender/sensor instead of a scan tool

Not checking for proper voltage at the ECM harness connector terminals when checking power and ground circuits

Not testing for interruptions in the signal wire between the ECM and oil pressure sensor/switch assembly

Failure to replace components such as the high-pressure oil pump, engine oil pressure switch, or damaged wiring when necessary

How serious is this?

A P0523 code is not considered to be serious under most conditions. It is usually a fairly simple diagnosis and code fix, however, there are some cases where it could point to more issues with the engine. In some cases, if ignored for too long, this code can point to a more serious problem. This issue could be an oil pump failure, resulting in catastrophic engine failure.

What repairs can fix the code?

repair manuals

The following are solutions that may fix this problem:

  • Clear the code and test the vehicle if it returns.
  • Examine the wiring and connections for looseness.
  • Recheck the car and make repairs and replacements as needed.
  • Check the engine and oil pathways if there are still issues, as well as any possible blockages.
  • Check for and repair any leaks.
  • If the engine is beyond repair or if it has a catastrophic failure, it may need to be replaced.

Related codes

A P0523 is related to and may be accompanied by the following codes:

P0505 – Engine Oil Pressure Sensor/Switch Low Input

P0500, P0502 – P0509, P0511-P0519, P0521-P0529, and P1016-P1023 – various engine oil pressure switch codes from other manufacturers.

How much does it cost to fix the P0523 code?

The repair cost of a P0523 code ranges between $150 and $500 depending on the type of repair that is required. Repairs other than simple oil pressure sensor replacement or repairs to the wiring could cost hundreds or even thousands of dollars.


In conclusion, the P0523 code is an OBD-II trouble code that references engine oil pressure sensor/switch high input. The best way to diagnose this code is with a scan tool or by checking for voltage at the ECM harness connector terminals. If the problem cannot be found using these, check the wiring and connections for looseness, as well as any possible blockages in the system. If there are no other issues discovered, it may have been caused by incorrect engine oil being used or improper maintenance on the vehicle. Fixing P0523 codes can range from simple to extremely expensive depending on what needs to be fixed.

P0523 Code – What Does It Mean & How To Fix It