Bosch CP3 Injection Pumps

Which CP3 do I need?

CP3s are matched to the engine and model year, not just the make. All five below are genuine Bosch remanufactured units, in stock and priced — no core to chase down first, no waiting on a bench slot.

If your truck sits between two of those ranges, or you are not sure which Duramax generation you have, call (530) 668-0818 with the VIN and we will confirm it in a minute.

How to tell whether the CP3 is actually the problem

A CP3 gets blamed for a lot of things it did not do. Before you replace one, it is worth ruling out the cheaper causes:

• Low rail pressure codes can come from a failing pump, but also from a plugged filter, a leaking injector return, or a bad rail pressure sensor. Return-flow testing tells them apart.
• Hard starting when hot is often injectors leaking down rather than the pump losing pressure.
• Metal in the fuel system. If a CP3 has come apart internally, debris travels downstream. Replacing the pump without cleaning the rails, lines and injectors gets you a second failed pump. On a contaminated system the injectors and rails have to be dealt with too.
• Fuel starvation. A CP3 is lubricated by the fuel passing through it. A weak lift pump or restricted supply will kill a new pump the same way it killed the old one.

We bench-test pumps and injectors and can tell you what the numbers actually say instead of guessing. If you would rather diagnose before buying, that is the better order of operations.

What “remanufactured” means on these

These are genuine Bosch reman units — disassembled, worn components replaced, reassembled and calibrated to Bosch specification, with the same Bosch part number the truck left the factory with. Valley Fuel Injection has been a Bosch factory-authorized diesel service center since 1993, which is why we sell Bosch reman rather than an unbranded rebuild of unknown origin.

Core charge and exchange

CP3 pricing includes a refundable core charge. Send your old pump back within 30 days and the core charge is refunded, provided it is rebuildable — no cracked housings, no fire damage, nothing missing. A prepaid return label is included. Full terms are on the exchange program page.

Warranty and shipping

Remanufactured injection pumps carry 12 months, unlimited mileage from date of purchase against defects in materials and workmanship. See the warranty page for full terms.

We ship nationwide from Woodland, California via UPS and USPS. Orders are processed within 1–2 business days; orders placed after 2:00 PM PST may not ship until the next business day. See shipping policy.

Common questions

Do I need to replace injectors at the same time? Not automatically. If the old pump failed catastrophically and sent debris downstream, yes. If it simply wore out, often not. Testing the injectors answers it — and testing eight is cheaper than replacing eight.

Is a CP3 swap onto a CP4 truck something you do? Call and ask with your specific truck. It is a common conversion but the details matter.

Can I send my own CP3 in to be rebuilt? Yes — see mail-in rebuild service. For CP3 specifically, the reman exchange above is usually faster and often costs about the same.

Other injection pump families

VP44 · VP30 · VE · CP4 · Stanadyne