P0087 means Fuel Rail/System Pressure Too Low. Fuel rail pressure is below what the computer is commanding. It is common on common-rail diesels and direct-injection gasoline engines. It is a generic OBD-II code, so the definition is the same on any make, but the most likely cause varies by engine; confirm with a scan tool and the service information for your vehicle before buying parts.
What P0087 means
Modern engines measure boost and fuel rail pressure and compare them with a desired value calculated from engine speed, load and throttle. When actual pressure falls short of desired for long enough, the computer sets a code and often reduces power to protect the engine. Watching desired and actual values side by side on a scan tool shows whether the shortfall is constant or only appears under load.
P0087 symptoms
- Hard starting or long cranking
- Loss of power or reduced-power mode
- Stalling under load
Common causes of P0087
- Clogged fuel filter
- Weak lift pump or in-tank pump
- Failing high-pressure pump, such as the CP3 used on many Cummins and Duramax engines
- Fuel pressure regulator or sensor faults
- Air in the fuel system or leaking injectors returning too much fuel
How to diagnose P0087
- Replace or check the fuel filter
- Measure supply pressure from the lift pump
- Compare desired and actual rail pressure on a scan tool
- Check injector return rates on diesels
Can you drive with P0087?
Not recommended: the engine may stall, and running a high-pressure pump starved of fuel can destroy it.
P0087 tips
On common-rail diesels, start with the fuel filter and the lift pump supply pressure, because a high-pressure pump starved of fuel wears quickly. Watch desired and actual rail pressure while a helper raises engine speed; actual pressure that falls away under load points to supply or a worn pump.
Will P0087 clear itself?
If the fault stops, the computer turns off the check engine light by itself after several drive cycles without seeing it again, and the code stays in memory as history for a while. Clearing P0087 with a scan tool after a repair is fine, but if the cause is still there the code returns, sometimes within one drive. Disconnecting the battery also clears codes on most vehicles, but it erases learned fuel trims and idle settings as well.
Related codes
| Code | Meaning |
|---|---|
| P0299 | Turbocharger/Supercharger A Underboost Condition |
| P0171 | System Too Lean (Bank 1) |
Guides that help
- fuel filter
- fuel pressure regulator
- engine sputtering
- diesel losing power
- diesel won’t start
- CP3 pump
- diesel lift pump
- fuel pump, filter and regulator symptoms
When it is more than a sensor
Our superchargers page lists supercharger kits, and diesel owners can read the 6.7 Cummins turbo guide. If a failed turbo or fuel pump has damaged the engine, compare engines by code on our engines page.
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