p0521
Moderate
Cadillac · Sedans
Engine Oil Pressure Sensor/Switch Circuit Range/Performance
Quick Answer
Error code P0521 on your Cadillac Sedans means: Engine Oil Pressure Sensor/Switch Circuit Range/Performance. This is usually fixable — see the step-by-step guide below.
Affected Models
Likely Causes
  1. Low engine oil level
  2. Faulty oil pressure sensor
  3. Worn oil pump
  4. Clogged oil filter
  5. Engine bearing wear
How to Fix It
1
Check engine oil level and condition
2
Replace oil filter
3
Test oil pressure with mechanical gauge
4
Verify oil pressure sensor output
5
Replace sensor if reading is incorrect
Pro Tip
This fix requires some technical knowledge. If you're unsure about any step, consider contacting support or a qualified technician.
Parts You May Need
Oil filter
Engine oil
Oil pressure sensor
Mechanical pressure gauge
Related Error Codes
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