P0521 – Meaning, Causes, Symptoms, & Fixes

Code P0521 Definition

Engine Oil Pressure Sensor/Switch Range/Performance

What Does P0521 Mean?

The oil pressure sensor calculates the oil pressure of the vehicle’s engine. This is then communicated to the ECM in the form of a voltage value. The P0521 code is set when the ECM detects the voltage value is either higher or lower than the specified acceptable range of oil pressure. This code can also be set when the engine detects constant fluctuation of the oil pressure value.

P0521 Symptoms

  • Check engine light
  • Oil pressure warning light
  • Oil pressure gauge too high/low
  • Engine stall

P0521 Causes

  • Low engine oil level
  • Faulty oil pressure sensor
  • Disconnected wiring in oil pressure circuit
  • Disconnected wiring in EGR circuit
  • Engine failure

Code P0521 Severity – Severe

Initially, this trouble code will not prevent your vehicle from regular operation. However, if not addressed early on, this code can cause serious internal damage to your engine causing complete engine failure. It is recommended to take your vehicle to the nearest dealership to have this code properly repaired to avoid costly repair(s).

Code P0521 Common Diagnosis Mistakes

Prematurely replacing the oil pressure sensor without visually inspecting the wiring of the oil pressure circuit for disconnection.

P0521 Diagnosis

  • Tools Needed to Diagnose:

Difficulty of Diagnosis and Repair

  1. Check to see if there are any other codes along with P0521 and clear your Check Engine Light with FIXD.
  2. Check the freeze frame data in an attempt to pinpoint the issue.
  3. Use the dipstick to check the oil level of your vehicle is sufficient.
  4. Verify the oil filter and drain plug are secure with no leakage.
  5. Visually inspect the wiring around the oil pressure sensor for disconnection.
  6. Check voltage of oil pressure sensor to ensure it is within specified range.
  7. If the problem persists, consider replacing the oil pressure sensor.
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Comments 1

Chester Parson

November 26, 2018

oil level was low. raised oil level to proper amount .erased code .SEEMS TO BE OK NOW.