Fuel Rail Pressure Sensor A Circuit Range/Performance
The P0191 code means the vehicle's onboard diagnostic system has detected: Fuel Rail Pressure Sensor A Circuit Range/Performance. This is a serious severity code.
- Keep driving?
- Yes, but fix soon
- DIY difficulty
- medium
- Estimated cost
- $80-$300 for a fuel rail pressure sensor replacement; $900-$2,000+ if the high-pressure fuel pump is the root cause (common on Ford EcoBoost and BMW turbo engines)
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Common Symptoms
- Check Engine Light on
- Engine stalls
- Hesitation under load
- Hard restart
- Fuel delivery inconsistency
Probable Causes (Ranked by Likelihood)
- Fuel rail pressure sensor reading outside expected range for conditions Very High
- Actual fuel pressure fault (pump, regulator, injector leak) High
- Sensor performance degradation Moderate
- Wiring intermittent fault Moderate
Step-by-Step Diagnostic Procedure
-
Monitor fuel rail pressure at idle, cruise, and WOT with a scan tool. Compare to factory specifications.
-
Verify actual fuel pressure with a mechanical gauge connected to the rail.
-
If actual pressure matches sensor reading but is out of spec, diagnose the fuel system.
-
If sensor reading differs from actual pressure, replace the sensor.
Common Fixes by Vehicle
What techs usually find when diagnosing P0191 on specific vehicles — tap your vehicle for the fix and the exact part:
2011-2020 Ford F-150/Explorer/Edge EcoBoost easy DIY
Fuel rail pressure sensor range/performance on EcoBoost engines means the sensor signal is erratic or outside expected parameters. The sensor is on the fuel rail and easy to access. Before replacing, clean the sensor connector and check for 5V reference voltage. A corroded connector or loose pin causes intermittent P0191. If the connector is clean and 5V reference is present, replace the sensor.
Labor: 15-30 min2010-2019 GM Silverado/Sierra/Tahoe GDI easy DIY
GM fuel rail pressure sensors fail from vibration and heat exposure. The sensor threads into the high-pressure fuel rail. Check for fuel leaking at the sensor threads -- a cracked O-ring causes pressure drops and erratic readings. Replace the sensor and O-ring. Torque the new sensor to 13 ft-lbs. Clear codes and test drive under load to verify the repair.
Labor: 15-30 min2011-2020 Ford Escape/Focus 2.0L EcoBoost easy DIY
On smaller Ford EcoBoost engines, P0191 can be caused by fuel quality issues in addition to sensor failure. Water or ethanol contamination in fuel causes rapid pressure fluctuations the sensor reports as out of range. If the code appeared after filling up at a new gas station, drain the tank and refill with quality fuel. If the code persists on good fuel, replace the sensor.
Labor: 15-30 minFrequently Asked Questions
Can low fuel pressure trigger P0191?
Yes. If the fuel pump cannot maintain adequate rail pressure under load, the sensor will read low and the PCM will set P0191 or P0087 depending on severity.
Sources
This page is built from documented references. Verify against your own service info before repair work.
P0191 on Diesel, EV & Equipment
The same code ID appears across other engines and platforms. The diagnostic flow varies by manufacturer — these are the platform-specific breakdowns:
See All Codes & Fixes for Your Vehicle
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