The P0523 code: Meanings, Causes, and Likely Fixes

P0523 refers to a OBD2 problem code. In layman’s terms, the code indicates the signal from the oil pressure sensor is higher than its normal operating range (in terms of voltage).

It is a generic term that can be applied to all cars, but it is more common for vehicles built by GM and Chrysler.

The most frequent cause of P0523 is a bad oil pressure sensor. But, this could be caused by an oil system fault. Don’t assume the sensor is bad until you confirm the oil pressure manually. If there’s an oiling issue, it can cause engine damage or failure.

P0523 Definition: Engine Oil Pressure Sensor/Switch – High Input

Here’s precisely what P0523 is telling you:

Oil Pressure Sensor/Switch

Oil pressure sensors bolt into an engine to relay the oil pressure readings from the Powertrain Control Module. This converts the mechanical pressure reading to a voltage value, which the PCM can understand.

The PCM transmits oil pressure from the PCM to the oil-pressure gauge (or warning lamp).

High-Input

It is nearly at its highest value or greater (which indicates to the PCM that oil pressure is high).

P0523 Symptoms

Below are the top symptoms of P0523.

• Check engine light
• A high reading of the gauge's oil pressure, or the light that indicates it could be on, can indicate excessive oil pressure.

There are many causes

There are two things going on. One, the oil pressure may be too high or the sensor is malfunctioning.

These are some of the more common reasons for P0523, and how to identify them.

Examine the oil

Verify that the oil level isn’t overly full. Does it feel sluggish? What is the correct weight of it? If you didn’t pour it in yourself, it’s possible that the wrong viscosity was used the last time the oil was changed. This is what you should do if P0523 appears right after an oil change.

Bad Oil Pressure Sensor – Wiring

If the oil level is correct, it’s not old, and it’s the proper viscosity, it’s time to look at the oil pressure sensor. These sensors are close to the exhaust and can cause widespread wiring problems.

Check the harness for damage. Look for cracked, broken, burnt, or brittle wiring. You should follow the wiring as closely as possible, however you must be within two feet of the plug.

The Oil Pressure Sensor can be tested

A simple multimeter can be used to test the oil pressure sensor/switch. You can see how it works for almost every oil pressure sensor in the video.

Another option is to purchase a mechanical oil tester at a Harbor Freight or AutoZone. They’re usually around $25-$40 and will 100% tell you if you have a real oil pressure problem. That’s about the same price as a new oil pressure sensor, and you’ll be plugging into that hole anyway.

Positive proof of a wiring or sensor problem can be found if the manual oil pressure is checked.

Mechanical Problems

While a bad oil pressure sensor or wiring issue is the most common cause of P0523, it’s not the only one. The code could also be caused by an oil pump failure or restricted oil flow. You can verify this with an oil pressure test kit (it’s just a mechanical oil gauge with adapters to fit most makes/models).

Conclusion

Although there may be a few problems that might cause P0523 to occur, the first thing you should do is check the oil. Also test the oil pressure sensor. More often than not, that’ll fix the code. Have fun!