P0191 — Fuel Rail Pressure Sensor Circuit Range/Performance
Seen on: Cummins · Detroit · Paccar MX
Fuel Rail Pressure Sensor Circuit Range/Performance. Common causes: Failing fuel pressure sensor, low fuel pressure, fuel leak.
Your code rides along, so nearby mechanics see the fault before they quote you.
How serious is it?
Serious. Power derate likely — plan to stop soon.
Most likely causes
- Failing fuel pressure sensor
- low fuel pressure
- fuel leak
- Weak fuel pump
- plugged fuel filter
- FCA/IMV valve worn
FAQ
Fuel Rail Pressure Sensor Circuit Range/Performance. Common causes: Failing fuel pressure sensor, low fuel pressure, fuel leak.
Serious — Power derate likely — plan to stop soon.
The most common cause is: Failing fuel pressure sensor. Other possibilities include low fuel pressure; fuel leak; Weak fuel pump; plugged fuel filter; FCA/IMV valve worn.
Power derate likely — plan to stop soon. When in doubt, get a qualified mobile diesel tech on the truck before continuing.
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.