{"product_id":"4352100c91-genuine-international®-diesel-exhaust-fluid-sensor-15-5-16-23g-qls-1-ssi","title":"4352100C91 | Genuine International® Diesel Exhaust Fluid Sensor 15.5\/16\/23G, QLS 1% SSI","description":"\u003cp\u003e\u003cstrong\u003eDescription:\u003cbr\u003e\u003c\/strong\u003eA Diesel Exhaust Fluid (DEF) sensor \u003cstrong\u003e4352100C91 \u003c\/strong\u003eis a key component in a diesel vehicle’s emissions control system, specifically within the Selective Catalytic Reduction (SCR) system. The DEF header (also called a DEF tank head or DEF sender assembly) is the unit mounted on or inside the DEF tank. It monitors and manages the Diesel Exhaust Fluid that’s injected into the exhaust to reduce harmful nitrogen oxide (NOx) emissions.\u003cbr\u003e\u003cbr\u003e\u003cstrong\u003ePart Number\u003c\/strong\u003e: 4352100C91\u003cbr\u003e\u003cstrong\u003eCondition\u003c\/strong\u003e\u003cspan\u003e: New\u003c\/span\u003e\u003cbr\u003e\u003cstrong\u003eManufacture\/Brand\u003c\/strong\u003e\u003cspan\u003e: International\u003cbr\u003e\u003c\/span\u003e\u003cstrong\u003e\u003cspan\u003e\u003cbr\u003e\u003c\/span\u003e\u003c\/strong\u003e\u003cstrong\u003eFits 4352100C91 \u003c\/strong\u003eFor \u003cspan\u003eNavistar \/ International\u003c\/span\u003e\u003cspan\u003e\u003cbr\u003e\u003c\/span\u003e\u003cb\u003eEngines: \u003c\/b\u003eCummins QSX15\u003cbr\u003e\u003cbr\u003e\u003cstrong\u003eSpecifications 4352100C91:\u003c\/strong\u003e\u003cbr\u003e\u003c\/p\u003e\n\u003ctable width=\"100%\"\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003ctd\u003e\n\u003cp\u003e\u003cstrong\u003eElectrical Connector:\u003cspan\u003e \u003c\/span\u003e\u003c\/strong\u003eDeutsch DT4 (STD)\u003cbr\u003e\u003cstrong\u003eSensor Type:\u003c\/strong\u003e\u003cspan\u003e \u003c\/span\u003eDigital (canbus)\u003cbr\u003e\u003cstrong\u003eDEF Header\u003c\/strong\u003e\u003cstrong\u003e\u003cspan\u003e \u003c\/span\u003eHeight (IN):\u003cspan\u003e \u003c\/span\u003e\u003c\/strong\u003e27\u003cbr\u003e\u003cstrong\u003eDEF Suction\u003c\/strong\u003e\u003cstrong\u003e\u003cspan\u003e \u003c\/span\u003eFitting Dia. (IN):\u003cspan\u003e \u003c\/span\u003e\u003c\/strong\u003e3\/8 SAE J2044\u003cbr\u003e\u003cstrong\u003eDEF Return\u003cspan\u003e \u003c\/span\u003e\u003c\/strong\u003e\u003cstrong\u003eFitting Dia. (IN):\u003cspan\u003e \u003c\/span\u003e\u003c\/strong\u003e5\/16 SAE J2044\u003cbr\u003e\u003cstrong\u003e\u003cspan\u003e\u003c\/span\u003eCoolant Inlet\u003c\/strong\u003e\u003cstrong\u003e\u003cspan\u003e \u003c\/span\u003eFitting Dia. (IN):\u003cspan\u003e \u003c\/span\u003e\u003c\/strong\u003e5\/8 Hose Bead\u003cbr\u003e\u003cstrong\u003e\u003cspan\u003e\u003c\/span\u003eCoolant Outlet\u003c\/strong\u003e\u003cstrong\u003e\u003cspan\u003e \u003c\/span\u003eFitting Dia. (IN):\u003cspan\u003e \u003c\/span\u003e\u003c\/strong\u003e5\/8 Hose Bead\u003cbr\u003e\u003cstrong\u003eIn-Tank Filter\u003c\/strong\u003e\u003cstrong\u003e:\u003c\/strong\u003e\u003cspan\u003e \u003c\/span\u003e40µ\u003cbr\u003e\u003cstrong\u003eTank Interface\u003c\/strong\u003e\u003cstrong\u003e:\u003c\/strong\u003e\u003cspan\u003e \u003c\/span\u003e6 Bolt\u003c\/p\u003e\n\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\n\u003cul id=\"catalogModels\" class=\"nav catalog\"\u003e\u003c\/ul\u003e\n\u003cp\u003e\u003cstrong\u003ePurpose of using 4352100C91:\u003c\/strong\u003e\u003cstrong\u003e\u003cbr\u003e\u003c\/strong\u003e\u003c\/p\u003e\n\u003ctable width=\"100%\"\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003ctd\u003e\n\u003col\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cstrong\u003e Monitor DEF Condition\u003c\/strong\u003e\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cp\u003eMeasures \u003cstrong\u003eDEF level\u003c\/strong\u003e, \u003cstrong\u003etemperature\u003c\/strong\u003e, and \u003cstrong\u003equality (urea concentration)\u003c\/strong\u003e.\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003eSends this data to the \u003cstrong\u003eengine control unit (ECU)\u003c\/strong\u003e so it can adjust DEF injection accurately.\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003eEnsures only properly mixed DEF (32.5% urea, 67.5% deionized water) is used — critical for emission compliance.\u003c\/p\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cstrong\u003e Supply DEF to the SCR system\u003c\/strong\u003e\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cp\u003eThe header connects to a \u003cstrong\u003eDEF pump\u003c\/strong\u003e that draws fluid from the tank and sends it through heated lines to the DEF injector in the exhaust.\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003eWithout the header’s pickup and delivery system, DEF couldn’t flow properly.\u003c\/p\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cstrong\u003e Maintain DEF Temperature\u003c\/strong\u003e\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cp\u003eIncludes a \u003cstrong\u003eheater element\u003c\/strong\u003e to prevent DEF from freezing in cold weather.\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003eEnsures DEF remains in a liquid state for reliable flow and injection.\u003c\/p\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cstrong\u003e Communicate with the Vehicle’s ECU\u003c\/strong\u003e\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cp\u003eThe header provides sensor data that helps the ECU determine:\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cp\u003eWhen to inject DEF\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003eHow much DEF to inject\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003eWhether there are faults (e.g., low DEF, poor quality, or freezing issues)\u003c\/p\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c\/li\u003e\n\u003c\/ol\u003e\n\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cbr\u003e\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eSigns of a Bad Diesel Exhaust Fluid Sensor 4352100C91:\u003cbr\u003e\u003c\/strong\u003e\u003c\/p\u003e\n\u003ctable width=\"100%\"\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003ctd\u003e\n\u003cp\u003e\u003cstrong\u003e1. Warning Lights and Fault Codes\u003c\/strong\u003e\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cstrong\u003e“Check Engine” light\u003c\/strong\u003e or \u003cstrong\u003e“DEF system fault”\u003c\/strong\u003e message on the dash.\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cstrong\u003eSCR or emissions-related fault codes\u003c\/strong\u003e (often starting with \u003cstrong\u003eP20xx\u003c\/strong\u003e, such as P203F, P205B, P206A, P207F).\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cstrong\u003eDEF quality sensor errors\u003c\/strong\u003e or \u003cstrong\u003etemperature sensor circuit faults\u003c\/strong\u003e stored in the ECM.\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cstrong\u003e“Service DEF system”\u003c\/strong\u003e or \u003cstrong\u003e“Vehicle will derate in XXX miles”\u003c\/strong\u003e messages.\u003c\/p\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003e\u003cstrong\u003e2. Incorrect DEF Level Reading\u003c\/strong\u003e\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cp\u003eDEF gauge shows \u003cstrong\u003eempty or full all the time\u003c\/strong\u003e, regardless of actual level.\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003eGauge fluctuates or drops suddenly after refilling the DEF tank.\u003cbr\u003e\u003cem\u003eCause:\u003c\/em\u003e DEF level sensor inside the header is malfunctioning or covered in crystallized DEF.\u003c\/p\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003e\u003cstrong\u003e3. DEF Freezing or Not Thawing\u003c\/strong\u003e\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cp\u003eIn cold weather, the system \u003cstrong\u003etakes too long to thaw\u003c\/strong\u003e or never thaws at all.\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003eThe engine may \u003cstrong\u003ederate\u003c\/strong\u003e because frozen DEF can’t be injected.\u003cbr\u003e\u003cem\u003eCause:\u003c\/em\u003e The \u003cstrong\u003eheater element\u003c\/strong\u003e in the DEF header has failed.\u003c\/p\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003e\u003cstrong\u003e4. DEF Quality or Concentration Errors\u003c\/strong\u003e\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cp\u003eECU reports \u003cstrong\u003epoor DEF quality\u003c\/strong\u003e or \u003cstrong\u003eincorrect urea concentration\u003c\/strong\u003e even when fresh DEF is used.\u003cbr\u003e\u003cem\u003eCause:\u003c\/em\u003e The \u003cstrong\u003equality sensor\u003c\/strong\u003e inside the header is faulty or contaminated with crystallized DEF.\u003c\/p\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003e\u003cstrong\u003e5. Engine Derate or Power Limitation\u003c\/strong\u003e\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cp\u003eThe truck goes into \u003cstrong\u003elimp mode\u003c\/strong\u003e or \u003cstrong\u003ereduces speed (e.g., limited to 5 mph)\u003c\/strong\u003e after warnings are ignored.\u003cbr\u003e\u003cem\u003eCause:\u003c\/em\u003e The ECM forces derate to prevent emissions violations if it detects the SCR system isn’t working properly.\u003c\/p\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003e\u003cstrong\u003e6. Crystallization or Contamination\u003c\/strong\u003e\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cp\u003eVisible \u003cstrong\u003ewhite crystals\u003c\/strong\u003e or buildup around the DEF tank or header connector.\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cstrong\u003ePoor electrical contact\u003c\/strong\u003e due to corrosion or DEF leakage.\u003cbr\u003e\u003cem\u003eCause:\u003c\/em\u003e DEF exposure to air causes crystallization, which can damage sensors or block passages.\u003c\/p\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\n\u003cp\u003e \u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cspan style=\"font-size: 0.875rem;\"\u003eAbout the Manufacturer – \u003c\/span\u003e\u003c\/strong\u003e\u003cstrong\u003eInternational \/ Navistar:\u003c\/strong\u003e\u003cbr\u003eInternational, a brand of \u003cstrong\u003eNavistar International Corporation\u003c\/strong\u003e, is a leading American manufacturer of commercial trucks, buses, and diesel engines. With a history dating back to the early 1900s, International is known for producing durable and reliable vehicles used in freight, construction, and municipal operations.\u003c\/p\u003e\n\u003cp\u003eNavistar has built a strong reputation in the trucking industry by focusing on innovation, performance, and long-term dependability. Their vehicles and components are trusted by fleets and drivers across North America and beyond.\u003c\/p\u003e","brand":"International","offers":[{"title":"Default Title","offer_id":50442781262071,"sku":"4352100C91","price":499.0,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0895\/7080\/3959\/files\/photo_2025-04-03_22-55-57_748x748_6cb91aaa-2487-415f-a1ee-32a9b8dce403.jpg?v=1768948214","url":"https:\/\/forcetruckparts.com\/products\/4352100c91-genuine-international%c2%ae-diesel-exhaust-fluid-sensor-15-5-16-23g-qls-1-ssi","provider":"Force Truck Parts","version":"1.0","type":"link"}