GM V8 P0521, P0522 & P0523: understand the oil pressure concern

What are P0521, P0522 and P0523 code definitions?

P0521- Engine oil pressure sensor performance
P0522- Engine oil pressure sensor circuit low voltage
P0523- Engine oil pressure sensor circuit high voltage

What Does P0521, P0522 and P0523 Mean?

These codes concern the oil-pressure sensor’s performance or electrical signal. A circuit-low code does not, by itself, establish low mechanical oil pressure; a circuit-high code does not establish high mechanical pressure. Use the diagnostic procedure, circuit identification and specifications for the exact engine. A code alone does not identify the failed component.

What are the symptoms of P0521, P0522, P0523?

• Check engine light

• Low oil pressure warning message

• Inoperative oil pressure gauge

What are the common causes of GM trouble codes P0521, P0522, P0523?

• Sensor: An inaccurate or missing signal is one possibility. Verify the signal and circuit using the applicable service procedure before replacing the sensor; this guide does not establish how likely that cause is on your vehicle.

• Screen, where fitted: A restriction may affect the sensor reading. GM bulletin PIP4786A addresses listed applications with a low-pressure message or P0521. When service diagnosis finds low scan-tool pressure but correct pressure at the oil-filter housing, it calls for inspecting the valve-lifter oil filter before replacing parts. Read GM’s application list and procedure (PDF).
  See the screen inspection in GoTech’s replacement guide →

• Connector and wiring: Identify the reference, signal and ground from the correct circuit diagram. Test using application-specific specifications; the code alone does not distinguish a sensor fault from a circuit fault.
  
  Actual low oil pressure: A mechanical pressure problem also needs consideration. Establish the pressure condition rather than assuming that a sensor-related code rules out an engine lubrication concern.

GoTech tip · Verify the pressure concern. A full oil level and a quiet engine do not confirm normal oil pressure. Verify the pressure concern using service information for the exact engine before treating it as a sensor fault.

Can I still drive my car with a P0521, P0522, or P0523 code set?

These codes alone do not establish that the vehicle is safe to drive. Follow the vehicle’s oil-pressure warning instructions and establish whether actual pressure is low. Do not use a quiet engine or a full dipstick as clearance to keep running it; arrange appropriate diagnosis if pressure cannot be verified.