Buy Genuine CAT DEF Injector Assembly for CAT C7.1 Front - wisentpartscenter.com

Description

Cat 0-444-043-118 DEF Injector Assembly – Genuine Caterpillar Denoxtronic 2.2 Doser for C7.1

The Cat 0-444-043-118 is a genuine Caterpillar DEF doser injector, the Bosch Denoxtronic 2.2 unit used on the C7.1. It mounts on the exhaust and is the piece that actually sprays diesel exhaust fluid into the stream ahead of the SCR catalyst. The ECM tells 0-444-043-118 how much to dose based on exhaust flow and temperature, and the spray coming out of 0-444-043-118 has to atomize properly so the fluid turns to ammonia and reacts evenly across the catalyst. Coolant runs through the body to keep it from cooking against the exhaust heat.

Key Functions:

- Sprays metered DEF into the exhaust ahead of the SCR catalyst
- Doses off ECM commands based on exhaust flow and temp
- Coolant cooled body handles the heat where it mounts
- Delivers the atomized spray pattern the catalyst needs for NOx conversion

Fitment & Specifications:

- Genuine Cat DEF doser injector, part number 0-444-043-118
- Bosch Denoxtronic 2.2 system
- For Cat C7.1 engines
- Coolant cooled, with DEF supply and coolant connections

Verify fitment by engine or machine serial number before ordering.

Purpose of the Part

0-444-043-118 is the last piece in the DEF system and the one that puts the fluid into the exhaust. Everything upstream of it, the tank header, the pump and the lines, is just moving DEF to this point. The ECM figures out how much the exhaust needs based on flow and temp and commands 0-444-043-118 to spray that amount. The spray pattern matters just as much as the volume, the DEF has to atomize and mix in evenly so it converts to ammonia and reacts across the whole catalyst instead of piling up in one spot. Coolant circulates through 0-444-043-118 because it is bolted straight to hot exhaust, without that flow the fluid inside would boil and the internals would not last.

Issue Symptoms / When to Replace

The usual sign is an SCR efficiency code and a derate while the rest of the DEF system checks out fine. Crystallized urea around the tip of 0-444-043-118 or in the pipe right behind it is the classic one, that means it is not atomizing right or it is leaking by. A plugged or restricted 0-444-043-118 shows up as DEF pressure faults because the pump is pushing against a blockage. A leaking one wets the pipe and leaves white residue at the mounting flange. Machines that idle a lot are harder on these since the exhaust never gets hot enough to burn off the deposits.

Before replacing 0-444-043-118, check the fluid with a refractometer, look at the tank and filter for debris, verify the pump is building pressure and make sure the coolant lines to 0-444-043-118 are flowing and not plugged. All of that throws similar codes and a restricted coolant circuit will take out a new injector the same way it took out the old one.

Signs to look for are SCR and DEF fault lights, staged derate down to limp mode, crystal buildup at the injector and in the pipe, DEF pressure or dosing faults, white residue or wet spots at the mounting flange, and less power on grades.

Related codes may include:

- P20EE SCR NOx catalyst efficiency
- P207F DEF quality
- plus machine specific J1939 and CDL codes for DEF pressure, dosing and injector circuit faults

Brand Information

Caterpillar has been building heavy equipment for over 95 years with a parts catalog running past 1.4 million numbers. On a DEF doser this matters because the ECM is dosing off an assumed spray pattern and flow rate, and 0-444-043-118 is built to that calibration. A unit that sprays even a little different will still bolt in and still leave the machine throwing SCR codes and derating. The Denoxtronic system behind 0-444-043-118 is Bosch built to CAT spec, which is what you want on a part that lives bolted to hot exhaust and handles a fluid that eats most materials.

Installation Notes

1. Fix any engine, EGR, DPF or DOC faults first, SCR codes usually come from something upstream.
2. Relieve pressure in the DEF lines and let the coolant cool down before opening anything.
3. Pull the old unit and check the mounting boss and the pipe for crystal buildup, clean it all out before 0-444-043-118 goes in, dropping a new injector into a plugged pipe will just take it back out.
4. Check the DEF filter and look in the tank for debris while you are in there.
5. Verify the coolant circuit is flowing, a plugged coolant passage will cook 0-444-043-118.
6. Install 0-444-043-118 with new seals and gaskets, keep the fittings clean since DEF picks up contamination easy.
7. Tighten the mounting hardware evenly and do not overtighten, the flange has to seal against the exhaust.
8. Hook up the DEF line, the coolant lines and the harness, make sure the plug is seated and locked.
9. Prime the system per the machine procedure so 0-444-043-118 is not running dry on startup.
10. Clear codes, let it cycle and confirm dosing and pressure are reporting right before it goes back to work.

How to Identify an OEM Part

A genuine unit has the markings cast right into the side of the body, not printed on or stuck on with a label. You should see the Bosch name and logo, the Denoxtronic model, the Bosch part number, the OEM part number, a date code and the country of manufacture. Check that the numbers on the side match what you ordered and that the casting itself looks like an OEM unit.

Why Buy 0-444-043-118 from Wisent Parts

  • ⏱️
    Fast shipping
    Orders before 12PM EST ship same business day.
  • 🛡️
    180-day warranty
    All parts covered from delivery date.
  • ↩️
    Easy returns
    30-day returns.
  • ✅
    Verify fitment
    Send VIN/ESN and we’ll confirm.

Shop with confidence

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.