DEF
Genuine OEM DEF Parts: Sensors, Multifunction Head Units & Doser Injectors
A flashing derate warning or a DEF fault code can shut your truck down in minutes — and every hour it sits is an hour it’s not earning. Most DEF system failures trace back to one of a handful of components: a worn level sensor, a cracked multifunction head unit, or a failing doser injector. Replacing it with the wrong part, or a cheap aftermarket substitute, often just brings the same fault code back a few weeks later. That’s why every DEF part in this catalog is genuine OEM, sourced directly against the manufacturer’s original part number.
What's in this category
This collection covers the core components of the Diesel Exhaust Fluid (SCR) system across heavy trucks, buses, and off-road equipment:
- DEF multifunction head units — the combined level, temperature, and quality sensor assembly mounted in the DEF tank
- Diesel exhaust fluid sensor heads — standalone level and quality sensors
- DEF header assemblies — tank header/cap assemblies that house the sensor and pickup tube
- DEF doser injectors — the metering injector that delivers fluid into the exhaust stream (Cummins B6.7, L9, X12, X15 and more)
- DEF wiring & tank jumper harnesses — the connecting harnesses between the sensor and the vehicle's ECM
Brands we stock
We carry genuine DEF parts for the OEMs running across North American fleets, including Freightliner, Spartan, Caterpillar, Cummins, International/Navistar, Volvo, Mack, Ford, Hyundai, Doosan, Bobcat, Terex, E-One, Gillig, TEMSA, Stewart & Stevenson, Hollingshead Mixer, Capacity, JLG, Ferrara Fire Apparatus, and Kalmar Ottawa. If you don’t see your exact OEM number listed, search by part number above or contact us — new listings are added regularly.
Why order DEF parts here
- Genuine OEM only — every part is matched to the manufacturer's original part number, not a generic equivalent
- Built for cross-reference — listings include the exact OEM number so you can verify fitment against your service manual or VIN before you buy
- Fleet-ready inventory — broad coverage across trucks, buses, fire apparatus, and off-road equipment, not just one brand
- Fast turnaround — ships quickly to keep your truck off the lift and back on the road
FAQ
What does a DEF multifunction head unit do? It's the sensor assembly mounted in the DEF tank that reports fluid level, temperature, and quality to the ECM. When it fails, the system often can't verify DEF quality and triggers a derate to protect emissions compliance.
How do I know if my DEF sensor is failing? An inaccurate level gauge, a DEF quality fault code, an unexpected derate, or a warning light that won't clear even after refilling with quality fluid.
Genuine OEM or aftermarket? All parts here are genuine OEM — no generic substitutes.
How do I find the right part? Match the OEM number on your old component, or check your service manual/VIN, then search that number above.
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8600553-2S Genuine Rosenbauer Cummins DEF Multifunction Head Unit
Rosenbauer CumminsProduct Overview The 8600553-2S is a genuine Rosenbauer Cummins DEF multifunction head unit designed for compatible diesel exhaust fluid system a...
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10019935 Genuine Blue Bird DEF Header
Blue BirdProduct Overview The 10019935 is a genuine Blue Bird DEF header designed for compatible diesel exhaust fluid system applications. It serves as a co...
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10027844 Genuine Blue Bird DEF Header
Blue BirdProduct Overview The 10027844 is a genuine Blue Bird DEF header designed for compatible diesel exhaust fluid system applications. It functions as a...
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10035950 Genuine Blue Bird DEF Header
Blue BirdProduct Overview The 10035950 is a genuine Blue Bird DEF header designed for compatible diesel exhaust fluid system applications. It provides DEF t...
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2888174 Genuine Cummins DEF Doser Injector
CumminsProduct Overview The 2888174 is a genuine Cummins DEF doser injector designed for compatible diesel exhaust fluid system applications. It meters an...
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5508583NX Genuine Cummins DEF Doser Injector
CumminsProduct Overview The 5508583NX is a genuine Cummins DEF doser injector designed for compatible diesel exhaust fluid system applications including B...
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5508583RX Genuine Cummins DEF Doser Injector
CumminsProduct Overview The 5508583RX is a genuine Cummins DEF doser injector designed for compatible diesel exhaust fluid system applications including B...
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8278348000 Genuine Gillig DEF Control Manifold Head Unit
GilligProduct Overview The 8278348000 is a genuine Gillig DEF Control Manifold Head Unit. This component operates within the DEF system by supporting die...
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31736 Genuine Newmar DEF Control Manifold Head Unit
NewmarProduct Overview The 31736 is a genuine Newmar DEF Control Manifold Head Unit. This component operates within the DEF system by monitoring fluid le...
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82-78348-000 Genuine Gillig DEF Control Manifold Head Unit
GilligProduct Overview The 82-78348-000 is a genuine Gillig DEF Control Manifold Head Unit. This component operates within the DEF system by monitoring f...
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SV10306 Genuine Wausau DEF Control Manifold Head Unit
WausauProduct Overview The SV10306 is a genuine Wausau DEF Control Manifold Head Unit. This component operates within the DEF system by monitoring DEF le...
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10563072 Genuine REV Group DEF Control Manifold Head Unit
RevFireGroupProduct Overview The 10563072 is a genuine REV Group DEF Control Manifold Head Unit. This component operates within the DEF system by monitoring DE...
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10345880 Genuine REV Group DEF Control Manifold Head Unit
RevFireGroupProduct Overview The 10345880 is a genuine REV Group DEF Control Manifold Head Unit. This component operates within the DEF system by monitoring DE...
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T434606 Genuine Perkins DEF Control Manifold Head Unit
PerkinsProduct Overview The T434606 is a genuine Perkins DEF Control Manifold Head Unit. This component operates within the DEF system by monitoring fluid...
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T431006 Genuine Perkins DEF Control Manifold Head Unit
PerkinsProduct Overview The T431006 is a genuine Perkins DEF Control Manifold Head Unit. This component operates within the DEF system by monitoring DEF l...
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3600932 Genuine LODAL DEF Control Manifold Head Unit
LODALProduct Overview The 3600932 is a genuine LODAL DEF Control Manifold Head Unit. This component operates within the DEF system by monitoring fluid l...
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SP222118 Genuine LiuGong DEF Multifunction Head Unit
LiuGongProduct Overview The SP222118 is a genuine LiuGong DEF Multifunction Head Unit. This component operates within the DEF system by monitoring fluid l...
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90035882 Genuine Kalmar Ottawa DEF Multifunction Head Unit
Kalmar OttawaProduct Overview The 90035882 is a genuine Kalmar Ottawa DEF Multifunction Head Unit. This component operates within the diesel exhaust fluid (DEF)...
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A052N293 Genuine Cummins DEF Header/Sensor With Tank
CumminsProduct Overview The A052N293 is a genuine Cummins DEF header and sensor assembly with tank designed for compatible diesel exhaust fluid system app...
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1554670 Genuine Spartan Grizzly DEF Sensor Head
SpartanProduct Overview The 1554670 is a genuine Spartan DEF sensor head designed for compatible diesel exhaust fluid system applications. It monitors DEF...
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4163695C91 Genuine International DEF Sensor 16/23G QLS SSI
InternationalProduct Overview The 4163695C91 is a genuine International DEF sensor developed for 16/23G QLS SSI diesel exhaust fluid system applications. It mea...
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2515985C3 Genuine International DEF Sensor 16/23G QLS SSI
InternationalProduct Overview The 2515985C3 is a genuine International DEF sensor engineered for 16/23G QLS SSI diesel exhaust fluid system applications. It det...
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4254216C91 Genuine International DEF Sensor 16/23G QLS SSI
InternationalProduct Overview The 4254216C91 is a genuine International DEF sensor designed for 16/23G QLS SSI diesel exhaust fluid system applications. It moni...
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2515986C1 Genuine International DEF Sensor 16/23G QLS SSI
InternationalProduct Overview The 2515986C1 is a genuine International DEF sensor designed for 16/23G QLS SSI diesel exhaust fluid system applications. It monit...
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