P0191: Fuel Rail Pressure Sensor A Circuit Range/Performance
Updated November 13, 2026
The fuel rail pressure sensor reports fuel pressure so the computer can control the fuel pump and injectors. P0191 means the reading is outside the expected range or doesn't match what the computer expects for current conditions. The sensor could be wrong, or the actual pressure could be off.
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🔧 Want to check this yourself? An OBD2 scanner reads the code; models with live data also show the sensor readings used in the checks below. See code readers and scanners from $24.99 ↓ · Which scanner do I need?
Common causes
- A faulty fuel rail pressure sensor
- Wiring or connector problems at the sensor
- Real low fuel pressure from a weak fuel pump or clogged fuel filter
- On direct-injection engines, a failing high-pressure fuel pump
- On some systems, a faulty fuel pressure regulator
Code meanings can vary slightly by manufacturer. Use these as a starting point and confirm with your vehicle's service information or a mechanic before replacing parts.
Symptoms
- Check engine light
- Hard starting or long cranking
- Hesitation or loss of power under acceleration
- Stalling
Is it safe to drive?
If the engine stalls, won't start, or loses power, don't drive it; have it towed. If it runs normally with a steady light, get it checked soon, since a fuel pressure problem can leave you stranded.
How to check it with a scanner
- Plug an OBD2 scanner into the port under the dashboard and read all stored codes and the freeze-frame data (the conditions when the code set).
- Scan for related fuel codes, such as P0087, lean codes or misfires.
- With a scanner, compare desired and actual fuel rail pressure in live data at idle and during gentle acceleration.
- With the engine off, inspect the sensor connector and wiring for corrosion or damage.
- Don't open fuel lines yourself, especially on direct-injection engines, where pressures are very high. Mechanical fuel pressure testing is a job for a shop.
- After a repair, clear the code and drive normally for a few days to confirm it doesn't come back.
A basic code reader shows the code; scanners with live data let you watch sensor readings, which is what you need for most of the checks above. See OBD2 scanners under $100.
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On some engines the fuel rail pressure sensor is part of the fuel rail and isn't sold separately; check your service information.
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Questions
What does P0191 mean?
P0191 is the generic OBD2 code for "Fuel Rail Pressure Sensor A Circuit Range/Performance." The fuel rail pressure sensor reports fuel pressure so the computer can control the fuel pump and injectors. P0191 means the reading is outside the expected range or doesn't match what the computer expects for current conditions. The sensor could be wrong, or the actual pressure could be off.
Is it safe to drive with P0191?
If the engine stalls, won't start, or loses power, don't drive it; have it towed. If it runs normally with a steady light, get it checked soon, since a fuel pressure problem can leave you stranded.
How do I check P0191 myself?
Read the code and freeze-frame data with an OBD2 scanner, then: Scan for related fuel codes, such as P0087, lean codes or misfires. With a scanner, compare desired and actual fuel rail pressure in live data at idle and during gentle acceleration. With the engine off, inspect the sensor connector and wiring for corrosion or damage. Don't open fuel lines yourself, especially on direct-injection engines, where pressures are very high. Mechanical fuel pressure testing is a job for a shop.
Related codes
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