This is the Bosch 0444042178, a new Denoxtronic DEF supply module made by Bosch. It is the pump unit that draws diesel exhaust fluid from the tank, builds pressure and feeds the dosing module. This one is the 12 volt version without a check valve. It crosses to Cummins 4387304, which Cummins has since replaced with 5418805, and to Cummins 2050811 and A052B661. It replaces the earlier Bosch 0444042132.

A supply module that has failed usually shows up as a DEF pressure or DEF dosing fault code, a low DEF pressure reading, a pump that will not prime or purge, or crystallized fluid around the module. The same codes can come from a plugged filter in the module, a frozen or kinked DEF line, bad fluid or a stuck dosing valve, so check those before replacing the pump. This is a replacement part for the factory selective catalytic reduction (SCR) system.

Specifications

Fits / Applications

• Cummins engines with a Bosch DEF system on 12 V that use supply module 4387304 or 5418805
• Cummins numbers 2050811 and A052B661
• Order by the number on the old pump and the system voltage. We do not list engine models because only one catalog names them.

Flush or replace crystallized DEF lines, fit clean fluid and check the tank pickup and the heater lines before running the new pump. Clear the fault codes and run the system’s prime and purge test after fitting.

Part Numbers & Cross Reference

Bosch 0444042178  ·  Bosch (replaced) 0444042132  ·  Bosch 0444042128  ·  Bosch 0444042179  ·  Bosch 098644D205  ·  Cummins 4387304  ·  Cummins (current) 5418805  ·  Cummins 2050811  ·  Cummins A052B661

Cross-reference numbers can change with engine serial, build year and emissions tier, so treat this list as a starting point. Send us your engine serial number and we will confirm the exact match against your build before anything ships. That check is free and takes a few minutes.

Frequently Asked Questions

What numbers does the Bosch 0444042178 replace?

Bosch 0444042132, 0444042128 and 0444042179, and Cummins 4387304, 5418805, 2050811 and A052B661. Cummins replaced 4387304 with 5418805.

What is the difference between the 0444042178 and the 044404229X?

Both are 12 V. The 0444042178 has no check valve and crosses to Cummins 4387304 and 5418805. The 044404229X has a check valve and crosses to Cummins 2871879 and 4387657. Order the number that is on your old pump.

Will it fit my Cummins engine?

It fits if your old supply module carries Bosch 0444042178 or 0444042132, or Cummins 4387304 or 5418805. Engines of the same size use different pumps by year and voltage, so call 530-668-0818 with your engine serial number.

Is this a new or remanufactured DEF pump?

It is a new supply module made by Bosch, not a rebuild.

Related Parts

• Cummins ISB & QSB 6.7L Medium-Duty Injector | 0986435697 | Bosch Authorized Remanufactured by VFI
• 2010-2016 Cummins ISB 6.7 Midrange (Rear Gear) CP3 Injection Pump | Bosch 0986437370 Remanufactured
• Cummins QSB6.7 Tier 4 Common-Rail Fuel Injector | Bosch 0445124019 New (Cummins 5289266)
• Cummins ISL & QSL 8.9L, Case IH, New Holland & Komatsu Fuel Injector | Bosch 0445120236 New (Cummins 5263308)

Why Buy From Valley Fuel Injection

We are a diesel fuel-injection and turbocharger shop in Woodland, CA, rebuilding pumps, injectors and turbos on our own benches since 1993, not a drop-ship storefront. When you call, you talk to the people who test these units. We verify fitment against your engine serial, VIN or build date before anything ships, so the right part arrives the first time.