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OBD code P0191

The fuel pressure sensor signal is not consistent with expected engine operation.

Estimated severity
High
Common symptoms
  • Hard starting
  • Power loss or limp mode
  • Jerking under load
  • Engine cuts out intermittently
  • Related fuel-pressure codes
Likely causes
  • Faulty rail pressure sensor
  • Connector with moisture, corrosion or poor contact
  • Wiring damaged by vibration or rubbing
  • Actual fuel pressure outside range
  • Fuel filter or fuel pump problem
Recommended checks
  1. 1. Check pressure reading with ignition on and engine off; it should be plausible.
  2. 2. Inspect the rail pressure sensor connector and wiring.
  3. 3. Compare actual and requested pressure during cranking.
  4. 4. Check sensor power supply and ground with a multimeter.
  5. 5. Also diagnose pump, filter and injectors if actual pressure does not follow demand.

What does code P0191 mean?

P0191 means the fuel rail pressure sensor is sending a signal that is out of range or not credible. The cause may be the sensor, damaged wiring or a real pressure problem. On modern diesel vans, it is important to distinguish a bad sensor from an actual pressure fault before replacing expensive parts.

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