Powertrain, generic · Fuel and air metering, auxiliary emission controls
P00B9 Low Pressure Fuel System Pressure - Too Low. Low Ambient Temperature
Check engine lightOn
EmissionsRelevant
Drive cycleRequired
Limp modePossible
This code reports too low a pressure in the low-pressure fuel supply between the lift pump and the high-pressure pump under the additional condition of low ambient temperature. It separates cold-related supply problems from the general case. A typical mechanism, documented for diesel engines, is wax separating from insufficiently winterised fuel at sub-zero temperatures and clogging the filter or tank strainer. No manufacturer description naming this exact code, its thresholds or the vehicles using it was found.
Likely causes
Wax separation from summer or insufficiently winterised diesel in frost
Fuel filter clogged or water in the filter frozen
Fuel filter heater faulty
Lift pump weak
Symptoms
- Check engine light on
- Hard or no cold start
- Jerking or loss of power after starting
Repair estimate
DifficultyEasyDIY possible
Parts and labour€30–600
Time0.5–1.5 h
Typical range across vehicles; the real cost depends on what the testing finds.
Parts involved
fuel filterlow pressure fuel pumpfuel filter heaterlow pressure fuel sensor
Related codes
References: law.cornell.edu, static.nhtsa.gov, de.wikipedia.org.