Buy Genuine CAT DEF Pump 24V for C9.3 Top - wisentpartscenter.com

Description

Bosch 0-444-042-283 DEF Pump 24V – Genuine Bosch Diesel Exhaust Fluid Supply Pump for C9.3

The Bosch 0-444-042-283 is a genuine Bosch 24 volt DEF supply pump. It draws fluid from the tank, filters it and holds regulated pressure at the doser injector so the ECM can meter DEF accurately. On shutdown 0-444-042-283 reverses and pulls the fluid back out of the lines so nothing is left in them to freeze and split a line over the winter. Used on C7.1, C9.3, C15 and C18 engines.

Key Functions:

- Draws DEF from the tank and holds regulated pressure at the doser
- Filters the fluid before it reaches the injector
- Purges the lines back to the tank at shutdown to prevent freeze damage

Fitment & Specifications:

- 24 volt
- Engines C7.1, C9.3, C15, C18
- Wheel loaders 926M through 988K
- Excavators 313 through 395
- Dozers D6T through D9T
- Pavers AP1000, AP1055
- XQ series gen sets

Verify by engine or machine serial number before ordering.

Purpose of the Part

0-444-042-283 sits between the tank and the doser injector. It pulls DEF up out of the tank, runs it through a filter and builds the pressure the injector needs to spray properly. The ECM meters dosing based on the assumption that 0-444-042-283 is holding that pressure steady, so if pressure is low or swinging the dosing is off even though the injector itself is fine. The reverse purge at shutdown is the other half of the job, DEF freezes around 12 degrees F and expands, so pulling it back out of the lines is what keeps them from splitting.

Issue Symptoms / When to Replace

Most failures show up as DEF pressure faults and a derate. A worn or plugged 0-444-042-283 cannot build or hold pressure, which the ECM reads as a dosing problem. A plugged internal filter does the same thing and is worth checking before condemning the pump. If the purge function quits you get split lines and leaks after a cold night.

Common causes are contaminated fluid, debris pulled up from a dirty tank, and crystallized urea inside the pump from sitting. Check the DEF with a refractometer, look in the tank for sediment or crystal, and check the lines and connections for restriction before replacing 0-444-042-283, all of that throws the same pressure codes.

Signs to look for are DEF pressure faults, SCR derate, no or low pressure at the doser, audible pump running constantly or not running at all, leaks at the fittings, and crystal buildup around the pump.

Brand Information

The DEF supply pump is built by Bosch to CAT spec and calibrated to the pressure the machine's dosing strategy expects. CAT sells it as a matched part with the doser and tank header, which is why a genuine unit holds pressure the way the ECM assumes. Non genuine pumps commonly run at slightly different pressure, which still throws dosing and SCR efficiency codes even though the pump is new.

Installation Notes

1. Drain the coolant lines at the pump itself if it is coolant heated, it is quicker and cleaner than draining at the radiator.
2. Pull the protective cover and disconnect the harness, most use a locking clip that has to be released first.
3. Disconnect the DEF lines by squeezing the clips or releasing the C clips, expect fluid to drain out at this point.
4. Unbolt the pump and slide it out, typically 13mm hardware.
5. Check that the new 0-444-042-283 comes with the filter and any components you need before mounting it.
6. Mount 0-444-042-283 and snug the bolts evenly, do not overtighten, the housing is plastic and will crack.
7. Snap the DEF lines back in and reconnect the harness, make sure the locking clip is fully engaged.
8. Reconnect coolant lines if equipped and reinstall the cover.
9. Top off the DEF, clear the codes with a diagnostic tool and run a regen to finish the repair.

Before any of this, check the tank for sediment or crystal and replace the DEF filter, debris is what takes these pumps out and it will do the same to the new one.

How to Identify an OEM Part

A genuine unit has the CAT part number and serial number molded into the top of the housing, along with a data matrix code stamped on the case, not a printed sticker. The Bosch name, logo and Bosch part number are molded into the side of the pump body.

Why buy from Wisent Parts
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    180-day warranty
    All parts covered from delivery date.
  • ↩️
    Easy returns
    30-day returns.
  • ✅
    Verify fitment
    Send VIN/ESN and we’ll confirm.

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Warranty & Return Information
Warranty Information

Wisent Parts offers a 180-day warranty on all parts from the date of delivery. This warranty covers orders placed directly through our website. If a part fails during this period, we’re here to help - whether it’s a replacement, repair, or refund. For full details, refer to the Warranty page.

Return Information

Wisent Parts accepts returns within 30 days of delivery. All returns are subject to a restocking fee. To qualify, parts must be unused and in their original condition. For full return instructions and restocking fee details, please refer to the Returns page.