P0191: Fuel Rail Pressure Sensor Circuit Range/Performance Bank 1
Do not keep driving
Expect reduced power. Have actual rail pressure verified against the sensor's reported value with a separate gauge where possible, rather than trusting the sensor to report on itself.
What this code means
The rail pressure signal is electrically valid but does not agree with what the system should be producing. This is the code that catches a drifting sensor — one that still reports a smooth, plausible-looking value that happens to be wrong. It is worth taking seriously precisely because everything downstream trusts this number: a sensor reading low will drive the pump to over-pressure the rail while the module believes it is doing the right thing.
Likely causes
Start here
- Faulty fuel rail pressure sensor · moderate
- Restricted fuel filter · easy
- Worn high pressure fuel pump · specialist
- Failed fuel volume regulator · moderate
Less common
- Leaking fuel injector · moderate
- Weak low pressure lift pump · moderate
Symptoms
Components involved
Information, not instruction
CarGeek is a reference, not a service manual. Its pages are written from public sources and from what other people have found, never from a manufacturer's own service information, so they can be wrong or incomplete for your particular vehicle. Some of what they describe carries real risk: high voltage, fuel under pressure, stored energy, hot and moving parts.
Have anything you intend to act on checked by a trained person against the manufacturer's own procedure for your vehicle. Nothing here replaces that procedure.
Community experience
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