P0191
Medium SeverityFuel Rail Pressure Sensor Circuit Range/Performance
Fuel System
What Does P0191 Mean?
The fuel rail pressure sensor reading does not match expected values. Usually a sensor fault or wiring issue.
Common Fix
Replace fuel rail pressure sensor
Estimated Cost (DIY)
$30 - $80
Symptoms
- ⚠️Engine performance issues
- ⚠️Hard starting
- ⚠️Stalling
- ⚠️Check engine light
Common Causes
Faulty fuel rail pressure sensorlikely
Wiring issuepossible
Actual fuel pressure problempossible
How to Diagnose P0191
- 1Check sensor wiring
- 2Compare sensor reading to mechanical gauge
- 3Test fuel pump pressure
- 4Replace sensor if readings incorrect
Need to read or clear this code?
Shop OBD2 Scanners on Amazon →Frequently Asked Questions
- What does the fuel rail pressure sensor do?
- It monitors fuel pressure in the fuel rail so the ECM can adjust injector pulse width for proper fuel delivery.
- Is this sensor easy to replace?
- Usually yes — it screws into the fuel rail. Relieve fuel pressure first and have a rag ready for fuel spillage.