P00B9 OBD II Trouble Code Low Pressure Fuel System Pressure - Too Low, Low Ambient Temperature

How to quickly diagnose, repair, and info on symptoms and causes of a P00B9 code that means there is a problem within the low pressure fuel system pressure, being too low.

Symptoms of P00B9 OBD II Trouble Code

  • Low power
  • Limited output
  • Abnormal throttle response
  • Decrease fuel economy
  • Increased emissions
  • Sluggish
  • Engine noise
  • Hard start
  • Engine smoking on start-up

Common Causes of P00B9 OBD II Trouble Code

  • Dirty fuel
  • Extreme cold weather/temperature
  • Plugged fuel filter
  • Restricted fuel line (e.g. kinked, clogged, etc.)
  • Fuel pump pickup dirty
  • Unstable fuel
  • Fuel injector defective
  • Weak low pressure fuel pump
  • Sludgy fuel (e.g. old, thick, contaminated)

Severity of P00B9 OBD II Trouble Code

As explained earlier, low fuel pressures can and will cause issues in the future when diesel engines are concerned. I'd say severity would be set to moderate-high, because if you plan to drive your vehicle daily, and it's a diesel, you will need to make sure your fuel system is function adequately.