The 6.7 Cummins has spent most of its life on the Bosch CP3, a pump diesel people trust like an old pair of work boots. Then, for two model years, Ram switched to the Bosch CP4.2, and owners have been popping the hood to check ever since.
Knowing which one you have matters. The two pumps fail differently, require different service considerations and carry very different reputations at the parts counter. This page lays out the years, explains each pump in plain English and shows you how to read the tag.
We can help assess service options for both, and it all starts with a box and a shipping label.
Which Pump Is on My 6.7 Cummins?
| Model years | Trucks | High-pressure pump | What to know |
|---|---|---|---|
| 2007.5-2018 | Ram 2500 and 3500 pickups | Bosch CP3 | Three-piston workhorse; the 6.7 arrived mid-2007 |
| 2019-2020 | Ram 2500 and 3500 pickups | Bosch CP4.2 | Two plungers; sensitive to fuel quality, water and air |
| 2021-2024 | Ram 2500 and 3500 pickups | Bosch CP3 | Ram went back to the CP3 |
These rows describe well-known historical pickup configurations, not every engine revision or chassis-cab application. Later production changes and replacement work can alter what is installed, so use the complete pump number and the vehicle’s build information rather than deciding by model year alone.
The CP3: Old Faithful
The CP3 is a radial-piston pump: three pistons arranged around an eccentric cam, pushing fuel up to the common rail at very high pressure. Picture a tiny three-cylinder radial engine running backward, swallowing power instead of making it.
It does not time injection; the engine computer handles that by firing each injector. The CP3’s only job is pressure, and it does that job with plenty of margin. That is why it became the go-to swap for CP4 owners.
Numbers start 0 445 020, and Bosch reman units start 0 986 437 3. When a CP3 does fail, contamination is usually behind it: water, debris or neglected filters.
Shop Talk: HPFP means high-pressure fuel pump. On a 6.7 Cummins that is the CP3 or CP4.2, not the lift pump that feeds it.
The CP4.2: Lighter, Leaner and Picky About Fuel
The CP4.2 squeezes fuel with two plungers riding on a cam through roller tappets. It is compact and efficient, and with clean, dry fuel it does its job quietly.
The catch is how it fails. Poor lubricity, water or air in the fuel can wear the internals, and once metal starts to shed it travels downstream through the rail, lines and injectors. A failed CP4 is rarely a one-part repair. Numbers start 0 445 010, and Bosch reman units start 0 986 437 4.
Bench Notes: When a CP4 lets go, the pump is the headline but not the whole story. A proper repair checks the filters, rail, lines and injectors for debris, because a fresh pump in a dirty system is money down the drain.
Our CP4 failure guide covers the warning signs, and the CP4 vs CP3 conversion guide explains the swap many 2019-2020 owners consider.
Did You Know? The same CP4.2 family shows up on the 6.7 Power Stroke and the LML Duramax, so all three big diesel pickup brands have spent time with it.
Common 6.7 Cummins Fuel System Problems
- Low rail pressure codes such as P0087, from a weak lift pump, clogged filters or a tired high-pressure pump.
- Water in the fuel. Bad for any pump, worst for the CP4.2.
- Hard starts, stalling and power loss. Our hard start and smoke guide helps sort pump from injector.
- Glitter in the filters. Metal flakes are a red flag for CP4 wear; park it and call us.
- Leaks. Seals and fittings on older CP3s. See our injection pump leaks guide.
How to Tell Which Pump You Have
Check the build date on the driver’s door jamb label first, then go to the pump itself. Read the complete Bosch and OEM numbers on the pump. Some number prefixes appear across more than one pump family, so the opening digits alone do not prove that a unit is a CP3 or CP4.
Owner’s Tip: Drain the water separator and change fuel filters on the schedule in your owner’s manual. Never loosen a fitting on the high-pressure side; common-rail systems run at pressures that can injure. Scan for codes instead and let the bench do the rest.
Ship It Right: Cap the inlet, outlet and return ports, drain what fuel you can and bag the pump before boxing it. If your CP4 failed, say so in your note so we know to look for debris.
Questions about 6.7 Cummins Injection Pump Repair
Should I convert my 2019-2020 Ram to a CP3?
Many owners do it for peace of mind. It is not required, and it takes the right parts and calibration to do well. Read the conversion guide, then use the repair inquiry form to talk through your truck.
My CP4 failed. Can you just rebuild the pump?
The serviceable condition of the pump is only one part of the decision. A CP4 failure that produces metal can contaminate other high-pressure components. The engine manufacturer’s specific inspection, replacement and cleaning procedure should guide the complete repair plan.
Will a CP3 from a 2015 fit my 2022?
Do not assume it will. We match pumps by part number and calibration, not just model year.
How is a 6.7 Cummins pump service scope determined?
For 6.7 Cummins Injection Pump Repair, the available path follows what inspection actually finds—not a universal rebuild recipe. DCT reviews the engine generation, original equipment, failure history and part number, whether the correct service parts and calibration information are available, and which work the customer chooses to authorize. Any exchange option is confirmed for the exact part rather than assumed from the family name. Explore how repair options are compared.
The 6.7 Cummins earns its keep dragging heavy things up long hills. Keep the pump that feeds it honest. Start a Mail-In Repair or request a repair evaluation, and let the test bench tell us exactly what your pump needs.