P0087

A trouble code records what a control module measured. It does not identify which part failed. Test before replacing anything.

Safe to drive

Minimize driving. Stalling and sudden power loss are likely. Stop immediately and do not restart if you smell or see fuel.

Urgency

Get it looked at now

Will it pass emissions

No

If ignored

On gasoline direct injection, sustained low rail pressure causes lean operation, misfire, and eventually catalyst damage from unburned fuel and heat. On diesel, the consequences are worse and faster. A pump starved of fuel or lubrication wears internally and sends fine metal through the rail into every injector — a repair measured in thousands of dollars that begins as a $150 filter. Ignoring the code while it intermittently limps also removes the warning that would have caught a fuel leak before it found an ignition source.

Check engine light

Solid

Clearing the light

A completed drive cycle is normally required before the monitor re-runs and the light can clear.

These are the causes this code can have. For the order to work through them in, see what to check first.

Ordering reflects how often each cause is responsible in general, not a probability for your vehicle. Confirm by testing.

In order. Each of these is cheaper or faster than what follows it, and each one can make the rest unnecessary.

1. Whether you can see or smell fuel anywhere, including on the engine and underbody

   This is a safety check and it comes first. A leaking high-pressure line or injector seal explains the pressure loss and represents a fire risk. Never search for a high-pressure diesel leak with your hands — the spray can penetrate skin and cause serious injury.

2. Actual fuel level and whether the correct fuel was put in

   It sounds trivial and it is regularly the answer. A faulty gauge, or gasoline in a diesel tank, produces exactly this code. Confirming it costs nothing and rules out the most embarrassing possibility before any tools come out.

3. Fuel filter service history and, on diesel, the water separator

   A clogged filter is one of the most common causes and by far the cheapest fix. Water in diesel fuel destroys the high-pressure pump, and draining the separator is a two-minute check that can prevent a five-figure repair.

4. Commanded versus actual rail pressure and the metering valve duty in live data

   It shows whether the system is trying and failing, and under what conditions. A shortfall only at high load points at supply volume; a shortfall at idle too points at a leak or a failing pump. This single reading shapes the entire diagnosis.

5. Low-pressure supply from the lift or in-tank pump

   The high-pressure pump can only compress what it is fed. A weak low-side pump produces identical symptoms to a failed high-pressure pump and costs a fraction to fix. Testing the cheap side first is the correct order every time. On a port-injected returnless system this circuit is the whole fuel system, so it is where the diagnosis both starts and usually ends.

1. Make it safe and inspect for leaks

   Tools Inspection light, cardboard, safety glasses, factory depressurisation procedure

   With the engine off and pressure relieved per the manufacturer's procedure, inspect all fuel lines, unions, the rail, injector seals, and the pump for wetness, staining, or fuel odour. Use cardboard and a light, never bare hands, on high-pressure lines. Do not proceed with running tests until the system is confirmed leak-free.

   Expected

   No fuel wetness, staining, or odour anywhere on the high-pressure side

2. Read freeze frame and identify the operating window

   Tools Scan tool with freeze frame

   Record engine speed, load, fuel level, coolant temperature, and rail pressure at the moment the code set. A code that only appears at wide-open throttle indicates a volume or supply limitation. A code present at idle or during cranking indicates internal leakage or a pump that cannot generate pressure at all.

   Expected

   A repeatable load and speed condition that reproduces the fault

3. Test the low-pressure supply side

   Tools Low-pressure fuel gauge, graduated container, factory specifications

   Measure pressure and flow volume at the filter outlet or the high-pressure pump inlet while the engine runs and under load. On a port-injected returnless system, measure at the rail test port or in line at the rail. Volume matters as much as pressure — a pump can hold static pressure and still not deliver enough flow. Specifications for supply pressure and volume are strictly vehicle-specific.

   Expected

   Supply pressure and flow volume both within the manufacturer's published figures

4. Inspect and, if due, replace the fuel filter and check for contamination

   Tools Filter tools, drain pan, white cloth or magnet for debris inspection

   Cut open or inspect the old filter element. Look for debris, rust, water, and especially fine metallic glitter. Metal in the filter means the high-pressure pump is already failing internally and changes the entire repair plan — replacing only the pump will result in a repeat failure.

   Expected

   Clean element with no water, sludge, or metallic particles

5. Verify the rail pressure sensor's plausibility

   Tools Scan tool with live data

   With the engine off and the system depressurised, the rail pressure sensor should read close to zero or atmospheric. A sensor with an offset error makes the ECU chase a pressure it already has. Compare its reading at key-on against the known depressurised state before condemning any mechanical component.

   Expected

   Near-zero rail pressure reading with the engine off and the system relieved

6. Watch the control valves work during a cranking and loaded test

   Tools Scan tool with data logging, oscilloscope for the valve control circuit

   On systems that have them, log metering valve or volume control valve duty cycle alongside actual rail pressure during cranking and under load. A valve commanded to maximum with pressure still falling short confirms the system has exhausted its authority. A valve not being commanded at all points at a circuit or module fault, not a mechanical one.

   Expected

   Valve command and rail pressure move together, with pressure reaching the setpoint

7. Test for internal leak-off — injectors and the pressure relief valve

   Tools Injector return test kit, factory test procedure, scan tool

   On common-rail diesel, run the manufacturer's injector back-leak test with return lines connected to graduated tubes; one injector returning far more than the others is leaking internally. Separately, check the rail pressure relief valve, which when stuck or blown dumps rail pressure straight to return and mimics a dead pump. On a port-injected system the equivalent check is a leak-down test for a bleeding injector or a failed regulator. Test procedures and acceptable return volumes are entirely vehicle-specific.

   Expected

   Return volumes even across injectors and within the published limit

8. Assess the high-pressure pump — after everything upstream is proven

   Tools Factory pump test procedure, inspection tools, scan tool

   Only once supply, filter, sensor, control valves, and leak-off are all verified good, evaluate the pump. On cam-driven gasoline direct injection pumps, inspect the pump follower and cam lobe for wear, which is a well-documented failure that mimics pump failure exactly. Follow the manufacturer's dead-head or capability test to confirm the pump cannot produce commanded pressure.

   Expected

   Pump reaches commanded pressure with the return blocked per procedure, and the follower shows no wear

This code has one of the widest legitimate cost ranges in OBD-II, and the order of diagnosis largely determines where you land in it. On a port-injected vehicle it is usually a filter or an in-tank pump and stops there. A filter and a water drain can be under $150. A gasoline direct injection pump with a follower is usually a four-figure job. A diesel common-rail pump that has failed and sent metal downstream routinely exceeds $6,000 because the rail, lines, injectors, and tank all have to be replaced or flushed. Insist on seeing the low-pressure supply test and the old filter cut open before authorising a pump. Ranges are US independent shop, parts plus labour; diesel and dealer pricing runs higher.

• Replacing the high-pressure pump first. It is the most expensive component and the diagnosis most often reached by assumption rather than testing. Supply-side and filter faults are more common and vastly cheaper.
• Assuming this is a direct injection code. P0087 is set by port-injected returnless systems too, where there is no high-pressure pump and the entire diagnosis is the in-tank pump, filter, regulator, and lines.
• Not testing the low-pressure supply. A weak in-tank or lift pump produces symptoms indistinguishable from high-pressure pump failure, and gets misdiagnosed constantly.
• Ignoring a stuck or failed rail pressure relief valve. It dumps rail pressure to return and makes a perfectly good pump look dead. On several common-rail platforms it is a known, inexpensive failure item.
• On diesel, replacing the pump without flushing or replacing the contaminated rail, lines, and injectors when metal debris is present. This is the classic repeat-failure scenario and it is expensive twice.
• On gasoline direct injection, replacing the pump without inspecting the cam follower and lobe. A worn follower destroys the new pump within weeks.
• Treating a fuel leak as a pressure problem. If fuel is escaping, that is a fire hazard first and a diagnostic clue second.
• Skipping the water separator on a diesel. Water is the fastest way to destroy a high-pressure pump and the cheapest thing on this list to check.

• Fuel Injector
• High Pressure Fuel Pump
• Fuel Pressure Regulator
• Fuel Rail
• Fuel Filter

• P0086Exhaust Valve Control Solenoid Circuit High Bank 2Severity level 3 of 5: Diagnose soon.moderate
• P0088Fuel Rail/System Pressure Too HighSeverity level 4 of 5: Get it looked at now.high

Definition

Generic code set (SAE J2012 / ISO 15031-6) via the OBDexopen database, dedicated to the public domain under CC0-1.0.

Diagnostic guidance

Written and reviewed in-house. See our editorial policy.

Review status

Reviewed

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