P0087
PowertrainFuel Rail/System Pressure - Too Low
The fuel rail pressure on your engine, almost always a diesel with this code, is below what the ECU has commanded. The fuel system isn't delivering enough pressure to inject properly.
ⓘ Information only. This page provides general educational information about fault code P0087. We do not assess the urgency or safety implications of any specific fault. That requires in-person diagnosis by a qualified mechanic. Full terms.
Recommended next steps
Whether a fault is urgent, drivable, or routine depends entirely on the cause on a specific vehicle, and that can only be determined by a qualified mechanic with diagnostic equipment. If a warning light is illuminated, the most reliable next step is professional diagnosis.
What does P0087 mean?
P0087 is a Powertrain (engine, transmission, fuel system) fault code. It indicates: Fuel Rail/System Pressure - Too Low.
This is a standardised OBD-II code. The technical definition is the same regardless of the make or model of vehicle, although specific causes and symptoms can vary between vehicles.
Symptoms commonly associated with this code
Symptoms that drivers often report alongside this code. Not all may apply to every case:
- • Hard or no starting, particularly when warm or cold
- • Loss of power, often accompanied by limp mode
- • Engine cutting out under load or at idle
- • Hesitation or surging when accelerating
- • Engine warning light
Possible causes
Causes commonly associated with P0087, listed in approximate order of typical investigation. The actual cause on a specific vehicle can only be confirmed by professional diagnosis.
- 1. Blocked or aged fuel filter, the cheapest and most common fix. If the filter is over its service interval, change it before doing anything else
- 2. Failed high-pressure fuel pump (HPFP). Common on older common-rail diesels at 100,000+ miles, and famously on some Mercedes and BMW engines well before that
- 3. Failed fuel pressure regulator (often called metering valve, MPROP, or DRV depending on the manufacturer)
- 4. Leaking injector return lines, fuel is going back to tank instead of staying in the rail
- 5. Air leak on the low-pressure (suction) side, weeping fuel filter housing or split low-pressure pipe
- 6. Lift pump failure on engines with one (the pump that delivers fuel from tank to HPFP)
How mechanics typically diagnose
A typical diagnostic sequence used by mechanics, provided here for educational reference only. Diagnostic work should be performed by a qualified mechanic with the appropriate tools and training.
- 1. Read live data, look at requested rail pressure vs actual. The gap tells you how badly it's failing to maintain pressure
- 2. Change the fuel filter if it's overdue. Don't underestimate this, blocked filters are responsible for a lot of P0087s
- 3. Check fuel filter housing for weeping. Air leaks here cause exactly these symptoms
- 4. Check the injector leak-off rates. Disconnect the leak-off pipes, run a clear pipe into a bottle on each, and idle for 30 seconds, an injector that fills the bottle disproportionately is leaking back
- 5. Test fuel rail pressure regulator by commanding pressure manually with a scan tool
- 6. If everything else is clear, fuel pump pressure tests, and at this point you're in workshop territory
Common questions about P0087
I have P0087 and the car won't start, what's the fastest check? +
Change the fuel filter and check the fuel filter housing for any sign of weeping or split clamps. Those two things solve a high proportion of P0087 starts. If it's still no-start after a fresh filter, you're likely looking at a fuel pump or injector return issue, and that's workshop work.
Could it be diesel bug or contaminated fuel? +
Yes, it's a real cause. Microbial growth (diesel bug) blocks filters faster than soot ever will. Contaminated fuel from a dodgy supplier or a diesel that's been standing for months is another cause. Drain a sample from the filter housing into a clear container, looking for cloudy, dark, or watery fuel.
Will a 'fuel system cleaner' additive fix it? +
No. Cleaners may marginally improve injector spray pattern over time but they don't unblock filters or restore pump pressure. Don't waste money on miracle additives if P0087 is set, the fault is mechanical.
Information only, not professional advice
The information on this page is provided for general guidance and educational purposes only. It is not a substitute for diagnosis or repair advice from a qualified mechanic. Always verify any fault before paying for repairs. carfaultcodes.co.uk accepts no liability for decisions made based on this information. Full terms →