P0521 — Engine Oil Pressure Sensor/Switch Range/Performance
What it means: Engine Oil Pressure Sensor/Switch Range/Performance.
How serious / can you keep driving: Caution. Limp to the next safe stop.
Check first: Compare mechanical gauge to sensor
Don't risk it — look up listed providers near you and give them this code when you call.
Listed providers nearest Salt Lake City, UT
Closest first. Tell them P0521 and what the truck is doing. RoadService.app lists these providers and does not employ them or carry out the repair.
- 0.0 mi away — based in Salt Lake City, UT · (801) 531-9256
- 0.0 mi away — based in Salt Lake City, UT · (385) 503-8084
- 0.0 mi away — based in Salt Lake City, UT · (385) 386-4700
Seen on: Heavy Truck
What P0521 means
Engine Oil Pressure Sensor/Switch Range/Performance. Common causes: Oil pressure sensor reading inconsistent.
How serious is it?
Caution. Limp to the next safe stop.
Most likely causes
- Oil pressure sensor reading inconsistent
- Aerated oil
- sensor fault
First moves (roadside)
- Compare mechanical gauge to sensor
- check for aeration in oil system
FAQ
Engine Oil Pressure Sensor/Switch Range/Performance. Common causes: Oil pressure sensor reading inconsistent.
Caution — Limp to the next safe stop.
The most common cause is: Oil pressure sensor reading inconsistent. Other possibilities include Aerated oil; sensor fault.
Limp to the next safe stop. When in doubt, get a qualified mobile diesel tech on the truck before continuing.
Related codes
Codes that commonly appear alongside P0521, or share the same subsystem.
- Engine Oil Pressure — Extremely Low (SPN 100 FMI 1)
- Oil pressure sensor — voltage high (SPN 100 FMI 3)
- Oil pressure sensor — voltage low (SPN 100 FMI 4)
- Engine Oil Pressure Too Low (P0524)
- Engine Oil Pressure Sensor/Switch Circuit Malfunction (P0520)
- Engine Oil Pressure Sensor/Switch Circuit Low Input (P0522)
- Engine Oil Pressure Sensor/Switch Circuit High Input (P0523)
Same symptom: Low oil pressure
Other codes a driver sees as an oil-pressure or oil-level warning.
- Engine Protection — Power Derate Active (SPN 1569 FMI 31) · Engine
- Trans oil pressure voltage high (SPN 1762 FMI 3) · Drivetrain & Transmission
- Trans oil pressure voltage low (SPN 1762 FMI 4) · Drivetrain & Transmission
- Trans oil temperature very high (SPN 177 FMI 0) · Drivetrain & Transmission
- Trans oil temperature voltage high (SPN 177 FMI 3) · Drivetrain & Transmission
- Trans oil temperature voltage low (SPN 177 FMI 4) · Drivetrain & Transmission
Find a mechanic or related guides
General diagnostic guidance for diesel engines (Cummins, Detroit, PACCAR, Volvo, Mack and more). Not a substitute for a scan-tool diagnosis on your specific truck.