Description
Why Your Truck Needs This DEF Filter?
The DEF (Diesel Exhaust Fluid) filter is a small but critical part of your SCR emissions system. It sits between the DEF tank and the dosing pump, trapping debris, crystallized urea and contaminants before they can reach — and destroy — your injector and dosing pump. A clogged DEF filter starves the SCR system of clean fluid, which triggers fault codes, forces the engine into derate (limp mode), and can eventually take your rig off the road. This direct-fit replacement kit restores proper DEF flow and protects the most expensive parts of your aftertreatment system.
Direct OEM Replacement, Fraction of the Dealer Price
This filter kit is engineered to the exact fit and filtration spec of the factory part. It drops into your existing DEF filter housing with no modifications, no special tools, and no dealer programming — a true 15-minute driveway fix. Replaces OEM part numbers 4388378 · A0001421089 · 2122909PE. Filter reference: UF106. Type: DEF (urea) pump / dosing filter, exhaust aftertreatment.
Key Features
- Direct fit for Detroit DD13 & DD15 — no cutting, splicing, or fabrication
- Protects the DEF dosing pump & injector from debris and urea crystallization
- Restores lost power — clears low DEF-pressure and derate fault codes
- OEM-spec filtration media — traps contaminants without restricting flow
- Complete kit — everything needed for a clean, leak-free service
- Heavy-duty construction — built for heat, vibration and urea chemistry
- Fraction of dealer cost — same fit and function, far lower price
Specifications
Item
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Specification
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Product Type
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DEF / Diesel Exhaust Fluid Urea Filter (Kit)
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Filter Reference
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UF106
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OEM Cross-Reference
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4388378 · A0001421089 · 2122909PE
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Filtration Media
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High-efficiency pleated synthetic media
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Function
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Protects SCR dosing pump & injector
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System
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SCR / Aftertreatment (exhaust)
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Condition
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100% New, Aftermarket
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Installation
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Direct replacement, no special tools
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Compatibility
Detroit Diesel (DD-Series)
Detroit DD13 :
Freightliner Cascadia, Western Star 5700XE / 4900
Freightliner Cascadia、Western Star 5700XE / 4900
Detroit DD15 :
Freightliner Cascadia, Western Star 5700XE / 4900
Freightliner Cascadia、Western Star 5700XE / 4900
Cummins (select engines, DEF filter compatible)
Cummins X15 / ISX
QSK19 / QSK23 / QSK60 / QSK78 / QSK95 / QST30
Mercedes-Benz / DAF (select EU trucks, compatible)
Mercedes-Benz OM471 / OM472 / OM473
DAF MX Series
⚠️Please verify before ordering:
DEF filter housing styles vary slightly by model year / emission standard (EPA10 / GHG14 / GHG17). Please verify against the part number on your existing filter (4388378 / A0001421089 / 2122909PE) or contact us.
Cross-Reference Numbers
4388378 (Fleetguard · Cummins)
A0001421089 (Mercedes-Benz / Detroit Diesel)
2122909PE
UF106
What's in the Box?
1 × DEF urea filter (UF106 cartridge)
Replacement O-ring seals (as included)
Note: Package contents are as per the actual product.
FAQ
Q1: Will this fix my DD15 DEF low-pressure / derate fault codes?
A1: If the codes point to low DEF pressure / restricted flow and the fluid level is normal, a clogged filter is the most common cause. Replacing it restores DEF flow and, in most cases, clears the derate and returns full power. If the code persists after replacement, inspect the DEF pump, injector, or crystallized urea lines.
Q2: How do I confirm this filter fits my truck?
A2: The most reliable way is to check the part number on your existing filter — if it matches 4388378, A0001421089 or 2122909PE, it's a direct swap. You can also send us your truck model, engine (DD13 / DD15 / X15, etc.) and year, and we'll confirm for you.
Q3: Does installation require a dealer or computer programming?
A3: No. This is a purely mechanical drop-in replacement — swap the cartridge and install the seals. No ECU flashing or programming needed; a skilled mechanic can finish in about 15 minutes.
Q4: How often should I replace the DEF filter?
A4: Follow the OEM service interval, or inspect every 100,000 miles / 160,000 km. If you frequently use lower-quality DEF fluid or have already seen DEF pressure warnings, replace it sooner.
Q5: Why does regular DEF fluid clog the filter?
A5: Low-quality or improperly stored DEF fluid crystallizes and sheds impurities, which build up on the filter and cause reduced flow, pressure warnings, and even pump damage. Use ISO 22241-compliant DEF and keep the system sealed.
Q6: Is this a genuine OEM or aftermarket part?
A6: This is a high-quality aftermarket part, manufactured to OEM specifications and dimensions. It fits and functions identically to the factory part at a much lower price — ideal for cost-conscious owner-operators, fleets, and repair shops.
Q7: Who is WAL?
A7: WAL Technology manufactures original equipment components for major heavy-duty truck fleets and engine builders globally, ensuring exact fitment and heavy-haul reliability.Engineered to meet demanding emission regulations worldwide (EPA / Euro VI), our filtration solutions are co-developed across 3 Global R&D Centers in Detroit (USA), London (UK), and Asia.
Q8: Why choose our UF106 filter kit?
A8: Prevents common fleet failures: USA Metal Vent Valve stops warping & leaks across extreme temperatures; Swiss Media delivers 99.1% efficiency @ 20µm & +15% dust capacity.
