Is P0087 always the high-pressure fuel pump?

No, and assuming so is an expensive mistake. The commonest causes are far cheaper: a blocked fuel filter, or air being drawn into the low-pressure supply at a filter housing seal or a perished pipe. Worn injectors leaking fuel back to the tank come next, and they mimic a failing pump almost exactly. The pump itself is genuinely responsible in a fair number of cases, but it should be the conclusion of a diagnosis rather than the starting point.

Can I keep driving with P0087?

You should not, and this is one of the few fuel codes where that advice is firm. If the high-pressure pump is wearing internally it releases fine metal particles into the fuel, and those travel through the rail and into every injector. Caught early the repair is a pump. Left to run, it becomes the pump, the rail, all the injectors and a full system flush, which is one of the largest bills an ordinary car can generate.

Will P0087 fail an MOT?

Yes, and likely on two counts. The engine management lamp is a major defect for diesels first used from 1 July 2008 and petrol cars from 1 July 2003, with 371,859 recorded failures against it. Separately, low rail pressure means poorly atomised fuel and dirty combustion, so a diesel stands a real chance of exceeding the smoke opacity limits measured during the emissions test.

Why does the car only lose power on hills with P0087?

Because that is when the fuel demand is highest. At light throttle the fuel system can usually keep up with a modest command, so the pressure matches and nothing looks wrong. Ask for full power up a long hill and the commanded pressure rises sharply; a restricted filter, air in the supply or a worn pump cannot meet it, the gap opens, and the control unit cuts power to protect the engine. That load-dependent pattern is a useful clue in itself.

Powertrain code · standard

P0087Fuel pressure genuinely too low

Standard definition: Fuel Rail/System Pressure Too Low

Last updated 27 July 2026

Quick answer

The sensor is working and it is telling the truth: there is not enough pressure in the fuel rail. This is a fuel supply fault rather than an electrical one, and on a high-mileage common-rail diesel it is one of the more serious codes you can be handed.

How the car works this out

The control unit commands a rail pressure appropriate to the load and monitors what the sensor reports back. When the actual figure sits below the commanded figure by more than the correction can close — and stays there — P0087 is stored. The important distinction from P0190 to P0193 is that nothing is wrong with the sensor or its wiring: the reading is believed, and it is bad news. Cars typically set this under load first, because that is when the demand is highest and any shortfall in supply shows up.

What you might notice

Sudden loss of power under acceleration, often on hills or when overtaking
Limp mode that clears on a restart and returns under load
Difficult starting, especially first thing in the morning
Rough running or a misfire at higher engine speeds
Cutting out at motorway speeds
A whine from the fuel tank area on some cars

What causes it

Most likely first. A code names the check that failed, not the part that failed it, so more than one of these can produce the same number.

1A blocked or long-overdue fuel filterCommon
How to check: Check the service history. If the filter is beyond its interval, replace it before investigating anything else — it is the cheapest possible outcome and a genuine cause.
2Air being drawn into the low-pressure supply, typically at the filter housing seal, a perished pipe or a hand priming pumpCommon
How to check: Fit a clear pipe section in the supply line and look for bubbles with the engine running. Air ingress is invisible in a black pipe and obvious in a clear one.
3Worn injectors leaking excessive fuel back to the tank, bleeding away rail pressure faster than the pump can build itCommon
How to check: An injector back-leak test, measuring the return volume from each injector. Ask for it by name before agreeing to any pump work.
4A worn high-pressure pump no longer able to reach the commanded pressurePossible
How to check: Compare commanded and actual pressure under full load, and have the back-leak test done first so that worn injectors are not mistaken for a worn pump.
5A faulty fuel metering or pressure regulating valve on the pumpPossible
6A weak lift pump or in-tank pump not supplying the high-pressure pump properlyPossible
7Contaminated fuel, including the wrong fuel put in at the pumpLess common

What to do about it

1Stop driving it hard. If the high-pressure pump is wearing internally, it sheds fine metal debris into the rail and injectors, and continuing to drive can turn a pump replacement into a whole-fuel-system replacement — comfortably the dearest outcome available on a modern diesel.
2Replace the fuel filter first if there is any doubt about when it was last done, and use the correct part rather than a generic one.
3Have the low-pressure side checked for air ingress before anything is dismantled. It is cheap to find and cheap to fix.
4Insist on an injector back-leak test before any high-pressure pump is quoted. Worn injectors and a worn pump produce almost identical symptoms and one of those repairs is far dearer than the other.
5Ask the garage to check the fuel for debris. If the pump has already broken up, replacing it alone will simply destroy the new one.

Can you keep driving?

Of all the fuelling codes, this is the one where continuing to drive can cost you the most. The car may feel fine at light throttle and only misbehave under load, which tempts people to nurse it along for weeks. If the cause is a disintegrating high-pressure pump, every mile pushes more metal through the rail and into the injectors. Get it diagnosed before you drive it further.

Will it fail an MOT?

The lamp is a major defect and one of 371,859 recorded failures, but the emissions consequence deserves as much attention. Fuel pressure determines how finely diesel is atomised as it leaves the injector, and poorly atomised fuel burns dirty. That shows up directly in the smoke opacity readings taken during the diesel emissions test, so a car with P0087 can fail on the lamp and on smoke on the same visit.

The light this turns on

Engine management lightThe engine management system has found a fault it cannot correct and has stored a code for it. The car will usually still drive, but an illuminated engine light is an automatic MOT failure on petrol cars first used from 1 July 2003 and diesels from 1 July 2008.

Common questions

Is P0087 always the high-pressure fuel pump?: No, and assuming so is an expensive mistake. The commonest causes are far cheaper: a blocked fuel filter, or air being drawn into the low-pressure supply at a filter housing seal or a perished pipe. Worn injectors leaking fuel back to the tank come next, and they mimic a failing pump almost exactly. The pump itself is genuinely responsible in a fair number of cases, but it should be the conclusion of a diagnosis rather than the starting point.
Can I keep driving with P0087?: You should not, and this is one of the few fuel codes where that advice is firm. If the high-pressure pump is wearing internally it releases fine metal particles into the fuel, and those travel through the rail and into every injector. Caught early the repair is a pump. Left to run, it becomes the pump, the rail, all the injectors and a full system flush, which is one of the largest bills an ordinary car can generate.
Will P0087 fail an MOT?: Yes, and likely on two counts. The engine management lamp is a major defect for diesels first used from 1 July 2008 and petrol cars from 1 July 2003, with 371,859 recorded failures against it. Separately, low rail pressure means poorly atomised fuel and dirty combustion, so a diesel stands a real chance of exceeding the smoke opacity limits measured during the emissions test.
Why does the car only lose power on hills with P0087?: Because that is when the fuel demand is highest. At light throttle the fuel system can usually keep up with a modest command, so the pressure matches and nothing looks wrong. Ask for full power up a long hill and the commanded pressure rises sharply; a restricted filter, air in the supply or a worn pump cannot meet it, the gap opens, and the control unit cuts power to protect the engine. That load-dependent pattern is a useful clue in itself.

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