P0523 Code: Engine Oil Pressure Sensor/Switch “A” Circuit High

What Does the P0523 Code Mean?

The P0523 code means that the engine oil pressure sensor/switch A circuit is high.

The Engine Oil Pressure Sensor communicates the engine oil pressure to the engine control module (PCM). If the PCM identifies an inaccurate signal from this sensor, it will trigger code P0523. Additionally, the low oil warning light on the instrument cluster may illuminate.

What are the Common Symptoms of the P0523 Code?

Check engine light comes on.
Engine stalls at idle
Engine runs rough or misfires

What are the Possible Causes of the P0523 Code?

The most likely cause of this code is a faulty oil pressure sensor or switch. The next most common culprit is defective wiring between the sensor and ECU, but an issue with either part can also cause it. Below are some common causes:

Faulty Sensor
Faulty Engine Oil Pressure Sensor
Faulty Wiring or Connectors
Oil Pump Malfunction
Oil Pressure Warning Light Circuit Problems

How to Diagnose the P0523 Code

Disconnect the negative battery terminal.
Remove the engine cover and then disconnect the electrical connector from the sensor. Use an ohmmeter to check for continuity between terminals 1 and 2 (black/yellow wire) and between terminals 3 and 4 (black/green wire). If either test fails, replace your oil pressure-sending unit with a new one from an auto parts store like AutoZone.

How to Fix the P0523 Code

Replace the oil pressure sensor.
Replace the oil pressure switch.
If applicable, replace the oil pressure relief valve and regulator to your vehicle.
Repair any intermittent open circuits in the engine oil pressure sensor/switch circuit.