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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.

Filters

$389.00 - $389.00
$389.00
$389.00 - $389.00
$389.00

4097727C91 Genuine International DEF Sensor 16/23G QLS SSI

International

Product Overview The 4097727C91 is a genuine International DEF sensor designed for 16/23G QLS SSI diesel exhaust fluid system applications. It moni...

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$389.00 - $389.00
$389.00
$389.00 - $389.00
$389.00
$389.00 - $389.00
$389.00
$389.00 - $389.00
$389.00

5012174R91 Genuine International DEF Sensor 16/23G QLS SSI

International

Product Overview The 5012174R91 is a genuine International DEF sensor designed for 16/23G QLS SSI diesel exhaust fluid system applications. It moni...

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$389.00 - $389.00
$389.00
$389.00 - $389.00
$389.00
$1,459.00 - $1,459.00
$1,459.00
$1,459.00 - $1,459.00
$1,459.00

04-31354-004 Genuine Freightliner DEF Header Assembly

Freightliner

Product Overview The 04-31354-004 is a genuine Freightliner DEF Header designed for factory diesel exhaust fluid system operation. This DEF header ...

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$1,459.00 - $1,459.00
$1,459.00
$1,459.00 - $1,459.00
$1,459.00
$1,099.00 - $1,099.00
$1,099.00
$1,099.00 - $1,099.00
$1,099.00

90035877 Genuine Kalmar Ottawa DEF Sensor Head Assembly

Kalmar Ottawa

Product Overview The 90035877 is a genuine Kalmar Ottawa DEF Sensor Head Assembly designed for factory diesel exhaust fluid system operation. This ...

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$1,099.00 - $1,099.00
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$1,099.00 - $1,099.00
$1,099.00
$1,398.00 - $1,398.00
$1,398.00
$1,398.00 - $1,398.00
$1,398.00

2516662C1 Genuine International DEF Tank Level Sensor

International

Product Overview The 2516662C1 is a genuine International DEF Tank Level Sensor designed for factory diesel exhaust fluid system operation. This se...

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$1,398.00 - $1,398.00
$1,398.00
$1,398.00 - $1,398.00
$1,398.00
$1,245.00 - $1,245.00
$1,245.00
$1,245.00 - $1,245.00
$1,245.00

DZ118293 Genuine John Deere DEF Tank Header Assembly

John Deere

Product Overview The DZ118293 is a genuine John Deere DEF Tank Header Assembly designed for factory diesel exhaust fluid system operation. This hea...

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$1,245.00 - $1,245.00
$1,245.00
$1,245.00 - $1,245.00
$1,245.00
$1,099.00 - $1,099.00
$1,099.00
$1,099.00 - $1,099.00
$1,099.00

DC4Z5J242A Genuine Ford Multifunction DEF Head Unit

Ford

Product Overview The DC4Z5J242A is a genuine Ford multifunction DEF head unit designed for compatible diesel exhaust fluid system applications. It ...

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$1,099.00 - $1,099.00
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$1,099.00
$1,289.00 - $1,289.00
$1,289.00
$1,289.00 - $1,289.00
$1,289.00

DM701-1800F765 Genuine Spartan Diesel DEF Sensor Head

Spartan

Product Overview The DM701-1800F765 is a genuine Spartan DEF Diesel Exhaust Fluid Sensor Head designed for factory DEF system operation. This senso...

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$1,289.00 - $1,289.00
$1,289.00
$1,289.00 - $1,289.00
$1,289.00
$1,069.00 - $1,069.00
$1,069.00
$1,069.00 - $1,069.00
$1,069.00

DM701-1800F766 Genuine Spartan DEF Multifunction Head Unit

Spartan

Product Overview The DM701-1800F766 is a genuine Spartan DEF Multifunction Head Unit designed for factory diesel exhaust fluid system operation. Th...

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$1,069.00 - $1,069.00
$1,069.00
$1,069.00 - $1,069.00
$1,069.00
$1,099.00 - $1,099.00
$1,099.00
$1,099.00 - $1,099.00
$1,099.00

DC4Z-5J242-A Genuine Ford Multifunction DEF Head Unit

Ford

Product Overview The DC4Z-5J242-A is a genuine Ford multifunction DEF head unit designed for compatible diesel exhaust fluid system applications. I...

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$1,099.00 - $1,099.00
$1,099.00
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$1,099.00
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$1,099.00

TMS00194H Genuine Temsa Bus DEF Multifunction Head Unit

TEMSA BUS

Product Overview The TMS00194H is a genuine Temsa Bus DEF Multifunction Head Unit designed for compatible DEF system applications. This multifuncti...

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$1,099.00 - $1,099.00
$1,099.00
$1,099.00 - $1,099.00
$1,099.00
$1,029.00 - $1,029.00
$1,029.00
$1,029.00 - $1,029.00
$1,029.00

90035845PS Genuine Kalmar Ottawa DEF Sensor Head Assembly 11.6 Inch

Kalmar Ottawa

Product Overview The 90035845PS is a genuine Kalmar Ottawa DEF sensor head assembly engineered for diesel exhaust fluid system applications. This m...

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$1,029.00 - $1,029.00
$1,029.00
$1,029.00 - $1,029.00
$1,029.00
$749.00 - $749.00
$749.00
$749.00 - $749.00
$749.00

4378050 Genuine Cummins Tank DEF Header

Cummins

Product Overview The 4378050 is a genuine Cummins tank DEF header used in diesel exhaust fluid system service. This header supports DEF tank monito...

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$749.00 - $749.00
$749.00
$749.00 - $749.00
$749.00
$375.00 - $375.00
$375.00
$375.00 - $375.00
$375.00

4157848C91 Genuine International 7 Gal Blow Molded DEF Tank Assembly

International

Product Overview The 4157848C91 is a genuine International 7 gallon blow molded DEF tank assembly used in diesel exhaust fluid system service. This...

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$375.00 - $375.00
$375.00
$375.00 - $375.00
$375.00
$375.00 - $375.00
$375.00
$375.00 - $375.00
$375.00

4097805C93 Genuine International DEF Tank Assembly

International

Product Overview The 4097805C93 is a genuine International 7-gallon DEF tank assembly used in the diesel emissions system. This blow-molded tank st...

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$375.00 - $375.00
$375.00
$375.00 - $375.00
$375.00
$375.00 - $375.00
$375.00
$375.00 - $375.00
$375.00

2526831C91 Genuine International DEF Tank Assembly

International

Product Overview The 2526831C91 is a genuine International 7-gallon DEF tank assembly designed for the diesel exhaust fluid system. It stores diese...

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$375.00 - $375.00
$375.00
$375.00 - $375.00
$375.00
$375.00 - $375.00
$375.00
$375.00 - $375.00
$375.00

4214372C93 Genuine International DEF Tank Assembly

International

Product Overview The 4214372C93 is a genuine International 7-gallon blow-molded DEF tank assembly designed to store diesel exhaust fluid for vehicl...

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$375.00 - $375.00
$375.00
$375.00 - $375.00
$375.00
$375.00 - $375.00
$375.00
$375.00 - $375.00
$375.00

4097805C92 Genuine International DEF Tank Assembly

International

Product Overview The 4097805C92 is a genuine International 7-gallon blow-molded DEF tank assembly used as the fluid reservoir within the SCR emissi...

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$375.00 - $375.00
$375.00
$375.00 - $375.00
$375.00
$375.00 - $375.00
$375.00
$375.00 - $375.00
$375.00

3998878C91 Genuine International DEF Tank Assembly

International

Product Overview The 3998878C91 is a genuine International 7-gallon DEF tank assembly built as a blow-molded reservoir for diesel exhaust fluid sto...

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$375.00 - $375.00
$375.00
$375.00 - $375.00
$375.00
$375.00 - $375.00
$375.00
$375.00 - $375.00
$375.00

4087179C91 Genuine International DEF Tank Assembly

International

Product Overview The 4087179C91 is a genuine International 7-gallon blow-molded DEF tank assembly designed to retain diesel exhaust fluid for vehic...

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$375.00 - $375.00
$375.00
$375.00 - $375.00
$375.00
$375.00 - $375.00
$375.00
$375.00 - $375.00
$375.00

4099788C91 Genuine International DEF Tank Assembly

International

Product Overview The 4099788C91 is a genuine International 7-gallon blow-molded DEF tank assembly developed to store diesel exhaust fluid for vehic...

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$375.00 - $375.00
$375.00
$375.00 - $375.00
$375.00
$375.00 - $375.00
$375.00
$375.00 - $375.00
$375.00

4099788C92 Genuine International DEF Tank Assembly

International

Product Overview The 4099788C92 is a genuine International 7-gallon blow-molded DEF tank assembly engineered to contain diesel exhaust fluid for SC...

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$375.00 - $375.00
$375.00
$375.00 - $375.00
$375.00
$1,099.00 - $1,099.00
$1,099.00
$1,099.00 - $1,099.00
$1,099.00

1009212002 Genuine RevFireGroup DEF Sensor Head Control Manifold

RevFireGroup

Product Overview The 1009212002 is a genuine RevFireGroup control manifold designed for diesel exhaust fluid system applications. This multifunctio...

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$1,099.00 - $1,099.00
$1,099.00
$1,099.00 - $1,099.00
$1,099.00
$1,199.00 - $1,199.00
$1,199.00
$1,199.00 - $1,199.00
$1,199.00

0431354001 Genuine Freightliner DEF Level Header 17.8 Inch

Freightliner

Product Overview The 0431354001 is a genuine Freightliner DEF level header developed for diesel exhaust fluid tank applications. This component is ...

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$1,199.00 - $1,199.00
$1,199.00
$1,199.00 - $1,199.00
$1,199.00