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Engine mechanicalSeverity High: diagnose before driving on

P0523Engine Oil Pressure Sensor/Switch "A" Circuit High

What it means

The oil pressure sensor signal voltage is higher than the sensor can normally produce (close to 5 V). Most often the signal wire or the sensor ground is open, or the signal is shorted to a supply voltage.

Symptoms

  • Oil pressure warning light
  • Possibly engine noise (ticking or knocking)
  • Reduced power on some engines

Common causes

  • Open signal wire (the ECU's pull-up then reads high)
  • Open or high-resistance sensor ground
  • Signal shorted to the 5 V reference or to battery voltage
  • Failed oil pressure sensor

What to check first

  1. Measure the voltage drop on the sensor ground with the key on (should be under 0.1 V)
  2. Unplug the sensor: the live data should jump to the opposite extreme
  3. Inspect the harness for chafing against other wires or hot parts
Can I drive with P0523? Not recommended. P0523 can lead to stalling, limp mode or engine damage; diagnose it before driving further.

Generic OBD-II meaning. Manufacturer-specific meanings and checks can differ; always check the service information for the car.

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P0523: questions and answers

What does P0523 mean?

P0523: Engine Oil Pressure Sensor/Switch "A" Circuit High. The oil pressure sensor signal voltage is higher than the sensor can normally produce (close to 5 V). Most often the signal wire or the sensor ground is open, or the signal is shorted to a supply voltage.

What are the symptoms of P0523?

Oil pressure warning light. Possibly engine noise (ticking or knocking). Reduced power on some engines.

What causes P0523?

Open signal wire (the ECU's pull-up then reads high). Open or high-resistance sensor ground. Signal shorted to the 5 V reference or to battery voltage. Failed oil pressure sensor.

How do you diagnose P0523?

1. Measure the voltage drop on the sensor ground with the key on (should be under 0.1 V) 2. Unplug the sensor: the live data should jump to the opposite extreme 3. Inspect the harness for chafing against other wires or hot parts

Can I drive with P0523?

Not recommended. P0523 can lead to stalling, limp mode or engine damage; diagnose it before driving further.