Trouble codes › Known problems › Diesel CP4 high-pressure fuel pump failure (Ram Cummins, Ford Power Stroke, GM Duramax)

Diesel CP4 high-pressure fuel pump failure (Ram Cummins, Ford Power Stroke, GM Duramax)

Codes: P0087

On heavy-duty diesel pickups with a Bosch CP4 high-pressure fuel pump, P0087 (fuel rail pressure too low) can be the first sign of the pump failing inside. When it fails, metal from the pump can spread through the injectors, rails and lines, and the engine can stall. 2019-2020 Ram Cummins trucks (recall 21V-880) and 2020-2022 Ford Super Duty diesels (recall 24V-957) have recalls; check your VIN.

Can I keep driving? Not if you can avoid it.

If P0087 comes with hard starting, power loss or stalling, stop driving and have it checked. A failing CP4 can shut the engine off without warning, and every mile it runs can spread more metal through the injectors.

Which vehicles

Why it happens

The CP4 is a high-pressure pump lubricated by the diesel fuel itself. Water, dirt and fuel with poor lubricity can wear its internal parts until they break up.

Once it starts coming apart, metal particles travel downstream to the fuel rails and injectors, so the repair often grows from one pump to the whole high-pressure system.

Ram's 2019-2020 recall covers pumps that can fail internally. Ford's 2020-2022 recall says deposits from aged biodiesel can form inside the pump and make it fail.

Older Ram Cummins trucks (2010-2018) and the 2017+ GM Duramax (L5P) use different pumps (CP3 and Denso), where low rail pressure is more often a filter, lift pump or relief valve problem.

Symptoms

  • Check-engine light with P0087, sometimes with P0088, P0191 or misfire codes
  • Hard starting, long cranking, rough idle or a loss of power
  • The engine stalling while driving and not restarting
  • Metal flakes or glitter in the fuel filter

How to confirm it

  1. Run your VIN at nhtsa.gov/recalls or with a dealer first: if a recall applies, the dealer does the work free.
  2. Check the fuel filters and drain the water separator; a clogged filter alone can set P0087.
  3. Cut open or inspect the old fuel filter for metal; metal is a strong sign the pump has failed.
  4. With a scan tool, compare desired and actual rail pressure while cranking and under load.

The repair

Recalls, bulletins and warranty programs

Recall 21V-880 (Ram Y78)
2019-2020 Ram 2500 and 3500 pickups and Ram 3500-5500 Chassis Cabs with the 6.7L Cummins (about 222,000 trucks): debris from an internally failed CP4 pump can cause a sudden loss of power. Dealers replace the high-pressure pump, inspect and replace other fuel parts as needed, and update the engine software.
Recall 24V-957 (Ford 24S78)
2020-2022 Ford F-250 through F-600 Super Duty with the 6.7L diesel (and 2021-2022 F-650 and F-750), about 295,000 trucks: aged biodiesel deposits can make the high-pressure pump fail. The remedy is a software update; Ford revised it in 2026, so a truck already done may need a second visit.
GM LML Duramax (2011-2016)
No GM recall for the CP4.2 pump was found. Ask a dealer whether any warranty help applies to your truck.

Programs can expire or depend on your VIN. Check nhtsa.gov/recalls and ask a dealer to run your VIN for open recalls, bulletins and extended coverage.

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Sources

Researched October 2026 from service bulletins, recall records and repair-industry reporting. Your vehicle may differ; confirm with your service information and a dealer before paying for major repairs.