Data report

CP4 Pump: Which Diesel Trucks Have It, Which Years Fail, and Why It Matters

Published October 4, 2026 · Updated October 10, 2026 · 10 min read

Mention a used diesel pickup and someone will warn you about the CP4. The warning is real but easy to attach to the wrong truck, because the Bosch CP4 high-pressure fuel pump is on specific engines and specific years. When it fails, it can stop the engine at highway speed and send metal through the whole fuel system; a 2016 Sierra 3500 owner told NHTSA the repair cost $16,145.

This guide puts every common diesel pickup in one table: which pump it has, how many NHTSA complaints describe a pump problem, and which recalls apply. It is built from NHTSA owner complaints, manufacturer recalls and bulletins, and the records behind our engine guides, and it says plainly what nobody can tell you: the failure rate.

Which trucks have the CP4 pump

Pumps from our platform records and, for the Ram 2019-2020, Ram bulletin 14-008-22. Complaints: NHTSA owner complaints that clearly involve the diesel and describe a high-pressure pump problem (Ford Super Duty pulled 2026-09-12, GM HD 2026-09-29, Ram HD 2026-09-12 and 2026-10-10, Ram 5.9 2026-10-10, all NHTSA model names). For the Ram 2019-2020 the count is failures only; another 106 complaints are about waiting for the recall repair. Raw counts, not adjusted for how many trucks were sold.

Three trucks carry the CP4; the four below them are controls, trucks with a different pump and the same kind of owners, towing and fuel. On those, NHTSA complaints about the high-pressure pump are nearly absent. That is the strongest pattern in this guide: the complaints follow the pump, not the brand.

One more control is worth knowing about. The Ford 6.4 Power Stroke (2008-2010) used a Siemens K16 pump, and 8 complaints describe it failing. The CP4 is the best-known pump that sheds metal into a fuel system, but not the only one. aggregated

What year Powerstroke has the CP4?

Short answer: every 6.7 Power Stroke since the engine arrived in the 2011 Super Duty, through all three hardware generations, uses a Bosch CP4.2. The 6.4 (2008-2010) used a Siemens K16, and the 6.0 and 7.3 had no high-pressure fuel pump of this kind: their injectors are fired by engine oil. verified See our 6.7 Power Stroke guide by year.

What years did GM use the CP4?

Short answer: the Duramax LML, in 2011-2016 Silverado and Sierra 2500/3500 HD trucks. The earlier Duramax engines (LB7, LLY, LBZ, LMM, 2001-2010) used the Bosch CP3, and the L5P from 2017 uses a Denso HP4. verified See our Duramax LML guide.

What year did Dodge (Ram) use the CP4?

Short answer: on the Ram 2500 and 3500 with the 6.7 Cummins, the 2019 and 2020 model years. 2007.5-2018 trucks used the CP3. Ram's recall 21V-880 replaces the 2019-2020 pump with a CP3.3-style pump, and pump failure complaints almost stop after 2020. verified See our 2019 and later Ram 6.7 guide.

Why a CP4 failure costs so much

The pump itself is not the expensive part. What makes a CP4 failure a five-figure repair is where the metal goes.

1. The pump wears inside aggregatedShops and owners blame fuel with poor lubricity, water, air or dirt. Bosch and the truck makers have not published a single cause. Ford's 2024 recall names biodiesel deposits on the pump's rollers in 2020-2022 trucks.
2. Metal goes into the high-pressure side verifiedGM told its technicians to inspect the fuel pressure regulator for magnetic metal debris before replacing a pump (PIP4949).
3. The rails, injectors and lines are contaminated verifiedGM and Ram bulletins call for cleaning the whole fuel system and replacing contaminated parts (GM PIP5151, Ram 18-099-22).
4. The engine dies, often at speed verified134 of the 257 CP4 complaints describe a stall, a shut-off or a loss of power; 106 mention metal or contamination.

"The CP4 high pressure fuel pump has grenaded and sent metal all through my fuel system."

Owner of a 2019 Ram 2500, 2021. NHTSA complaint 11437226

CP4 failure by model year

Short answer: the complaints peak on 2020 Ford trucks (28), 2015-2016 LML trucks (25 and 21) and 2019-2020 Rams (25 and 38 failures). Every Ford 6.7 year from 2011 to 2022 has CP4 complaints, so no Ford year is clear of the risk.

Same complaint sets as the table above. A dash means no complaints in our data, or no CP4 on that truck that year (LML ended in 2016; the Ram row starts in 2019).

How to read this table. It counts complaints, not failures, and the trucks were not sold in equal numbers. 232 of the 257 CP4 complaints were filed in 2019 or later, as the trucks aged and the pump's reputation spread. The counts show where owners report trouble; they do not give your truck's odds.

CP4 pump failure symptoms

• Sudden loss of power, rough running and a stall that may not restart. Owners often describe it at highway speed, losing power steering and power brakes when the engine dies.
• A warning first, sometimes: a "change fuel filter" or fuel system message, limp mode, or an exhaust service message on some Rams.
• Codes: low or erratic rail pressure, such as P0087 and P0088, and on GM trucks P0191 and P128E; on Ram trucks P008A and injector circuit codes. verified
• Metal in the fuel filter or on the pressure regulator is the sign that matters most: it means the pump is coming apart.

"Later diagnosis at the Chevrolet dealership told me that the CP4 fuel pump disintegrated inside."

Owner of a 2011 Silverado 2500, 2018. NHTSA complaint 11150932

If it happens to you: stop cranking, have the truck towed, and ask the shop to check the fuel filter and the regulator for metal before replacing anything. A clogged filter, air or a weak lift pump can set the same codes, and those are cheap. aggregated

How much does a CP4 failure cost?

Owners reported $8,500 to $16,000 on Ford 6.7 trucks (2011-2025 complaints), $7,000 to $17,000 on the LML (2016-2025) and a $20,000 estimate on a 2019 Ram before the recall. The range depends on how far the metal got and what the shop replaced.

At list price, the pump is the small part: about $1,190 to $1,390 for a Ford CP4.2 and about $2,315 for GM's LML pump service kit. Ford fuel contamination kits with injectors, rails and lines list for about $4,345 to $7,554, and LML injectors for about $237 to $366 each, eight per engine. Labor and cleaning the tank and lines make up the rest.

CP4 recalls and programs

Check any VIN at NHTSA's recall lookup. verified

CP4 vs CP3: what is different?

Both are Bosch high-pressure pumps. In NHTSA's data the difference is stark: CP4 trucks draw dozens to over a hundred pump complaints each, CP3 trucks almost none. Shop guides explain it by design: the CP4 drives its pistons through rollers riding on a cam, lubricated only by the fuel, so poor fuel can wear that contact until it fails; the CP3 is described as more tolerant. aggregated We have not found a Bosch or manufacturer document that explains the difference, so treat the mechanism as the shops' explanation and the complaint gap as the evidence.

If you are buying a CP4 truck

• Run the VIN for 21V-880 on a 2019-2020 Ram and for 24V-957 and 26V-158 on a 2020-2022 Ford, and ask for the repair orders.
• Ask for fuel filter records and whether the water separator was drained. Water and dirt are the risk factors every source agrees on.
• Ask whether the pump has ever been replaced, and if so, what else was replaced. A pump-only repair on a contaminated system can fail again.
• Scan for fuel pressure codes, stored and pending.
• Pay a diesel shop to look at the fuel filter for metal if you are serious about the truck.
• Price the risk. A clean filter today does not prove the pump is healthy inside.

What we cannot tell you

• The CP4 failure rate. No one has published it. Complaint counts are not rates, the trucks sold in very different numbers, and owners report stalls more readily than slow failures. Anyone quoting an exact percentage is guessing.
• Why the pump fails. Fuel quality, water and air are blamed; Ford names biodiesel deposits for 2020-2022 trucks. No single cause is documented for all CP4 trucks.
• Whether additives, extra filters or software prevent it. None has published data behind it, including Ford's 2024 software recall.
• Whether a given truck's pump is worn. It cannot be seen from outside.

FAQ

Go deeper

Each of these pages shows the sources behind every claim, the confidence tier and the part numbers:

• Engine guides: 6.7 Power Stroke by year · Duramax LML · Ram 6.7 Cummins 2019+ · Ram 6.7 Cummins 2007.5-2018
• Failure modes: Ford 6.7 CP4 · LML CP4 · Ram 2019+ CP4
• Repairs: Ford CP4 contamination repair · Ford CP4 prevention · LML CP4 contamination repair
• Parts: Ford CP4.2 pump · Ford fuel contamination kit · LML pump service kit
• Platforms: Ford 6.7 · Duramax LML · Duramax L5P · Ram 6.7 2019+
• How we verify and tag facts

Sources. NHTSA owner complaints database (US government public domain), keyword-matched and limited to complaints that clearly involve the diesel, using the same complaint sets as our engine guides; owner quotes are taken from complaint narratives with capitalization normalized, and complaint numbers are given so you can read them in full. NHTSA recall records 21V-880, 24V-957 and 26V-158. Ram bulletins 14-008-22 and 18-099-22 and GM bulletins PIP4949, PIP5133, PIP5151 and PIE0523, from NHTSA's manufacturer communications index. Pump types from our platform records. Part prices are list prices at the time of publication. Torque Index aggregates and cross-checks public information, takes no paid placement and does not provide repair or inspection services.