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.
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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.