Error code
OBD2 P0091
OBD2P0091
Diagnostic Trouble Code· Standard OBD-II fault code read from the vehicle's onboard diagnostics.
What it means
Fuel Pressure Regulator 1 Control Circuit Low.
Severity
moderateCan drive but may experience performance issues and reduced fuel efficiency.
Summary
P0091 indicates that there is an issue with the fuel pressure regulator control circuit being too low on bank 1 of your engine. This can affect how well your car starts and runs.
Symptoms
- Hard starting
- No starting
- Poor performance
- Poor fuel economy
- Rough idle
- Cylinder misfire
Common Causes
- Wire harness problem due to poor repair practices, bad wire routing, or damage
- Faulty solenoid coil in the fuel rail pressure regulator
Diagnosis
- Check wire harness for damage
- Inspect FRP regulator connector for bent pins, corrosion, or water entry
- Test resistance in the FRP regulator circuit
Fixes
- Replace faulty fuel rail pressure regulator
FAQ
What should I do if my car has P0091?
You should inspect the wiring and connectors related to the fuel rail pressure regulator, and test for resistance issues. If problems are found, replace any faulty components.
Not affiliated with OBD2. Answer summarized from the manufacturer's manual linked above; consult that source for the authoritative procedure.
More OBD2 codes
- P0001Fuel Volume Regulator Control Circuit/Open
- P0002Fuel Volume Regulator Control Circuit Range/Performance
- P0003Fuel Volume Regulator Control Circuit Low
- P0004Fuel Volume Regulator Control Circuit High
- P0005Fuel Shutoff Valve 'A' Control Circuit/Open
- P0006Fuel Shutoff Valve 'A' Control Circuit Low
- P0007Fuel Shutoff Valve 'A' Control Circuit High
- P0008Engine Position System Performance
- P0009Engine Position System Performance
- P0010'A' Camshaft Position Actuator Circuit
- P0011'A' Camshaft Position - Timing Over-Advanced or System Performance
- P0012'A' Camshaft Position - Timing Over-Retarded