Error code

OBD2 P0191

OBD2P0191
Diagnostic Trouble Code· Standard OBD-II fault code read from the vehicle's onboard diagnostics.

What it means

Fuel Rail Pressure Sensor Circuit Range/Performance.

Severity

moderateCan drive but with reduced performance; not recommended for long distances.

Summary

P0191 indicates a problem with the fuel rail pressure sensor circuit on your vehicle's high-pressure fuel injection system, which can affect engine performance and fuel economy.

Symptoms

  • Engine may not start or run poorly
  • Decreased power and fuel efficiency

Common Causes

  • Fuel rail pressure sensor failure due to heat and vibration
  • Wiring issues such as chafing, poor routing, bent pins, or corrosion

Diagnosis

  1. Check wire harnesses and connectors for damage
  2. Test circuit continuity and resistance between sensor and ECM
  3. Backprobe the RPS or ECM to check voltage against specifications

Fixes

  • Replace faulty fuel rail pressure sensor

FAQ

What should I do if my car has P0191?

Check for wiring issues and test the fuel rail pressure sensor. If problems persist, replace the sensor.

Is it safe to drive with P0191?

Driving is possible but performance will be reduced; addressing the issue promptly is recommended.

View source

Not affiliated with OBD2. Answer summarized from the manufacturer's manual linked above; consult that source for the authoritative procedure.

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