4097728C91 | Genuine OEM International DEF QLS Header

The Genuine OEM International / Navistar 4097728C91 DEF Quality Level Sensor (QLS) Header is designed for compatible commercial diesel trucks equipped with 10.6-gallon, 15.9-gallon, or 25.2-gallon Diesel Exhaust Fluid (DEF) tanks. This ultrasonic DEF tank header monitors fluid conditions and communicates important information to the vehicle's emissions control system.

As part of the Selective Catalytic Reduction (SCR) system, the DEF QLS header helps maintain accurate DEF monitoring and supports proper emissions system operation.

PRODUCT INFORMATION

• Part Number: 4097728C91

• Brand: International / Navistar

• Condition: Not specified

• Component: DEF Quality Level Sensor Header

• Part Type: DEF Tank Head Unit / QLS Sensor Assembly

• Sensor Technology: Ultrasonic

• Tank Capacities: 10.6 / 15.9 / 25.2 Gallons

• System: Diesel Exhaust Fluid (DEF) / Selective Catalytic Reduction (SCR)

• Sensor Functions: DEF Level, Quality, and Temperature Monitoring

• Installation Location: DEF Tank

• Application: Commercial Diesel Trucks

• Emissions Application: Selected 2017 and newer federal emissions configurations

• Fuel Type: Diesel

• Engine Applications: Vehicle- and emissions-system-specific

• Electrical Connector: Verify against the original assembly

• Mounting Configuration: Verify against the original DEF tank

• Related Service References: 4140918C91, 4254210C91, 2517604C1

• Kit Contents: Verify against the actual product

APPLICATIONS

The International 4097728C91 DEF QLS Header is intended for compatible International / Navistar commercial vehicles equipped with the appropriate DEF tank and SCR emissions system.

Potential applications include:

• International / Navistar Heavy-Duty Trucks

• International Commercial Diesel Vehicles

• Selected Medium-Duty Diesel Trucks

• Vehicles with Compatible 10.6-Gallon DEF Tanks

• Vehicles with Compatible 15.9-Gallon DEF Tanks

• Vehicles with Compatible 25.2-Gallon DEF Tanks

• SCR Emissions Systems Requiring OEM Part Number 4097728C91

International service documentation identifies this part for selected 2017 and newer federal emissions configurations.

Important: DEF tank capacity alone does not guarantee compatibility. Verify the original OEM part number, sensor generation, tank depth, mounting arrangement, electrical connections, and vehicle VIN before purchasing.

FUNCTION

The International 4097728C91 DEF QLS Header monitors Diesel Exhaust Fluid conditions inside the vehicle's DEF tank.

The ultrasonic sensing system provides DEF level, quality, and temperature information used by the electronic control system to support SCR operation and emissions diagnostics.

A worn, damaged, or failing DEF QLS header may cause symptoms such as:

• Incorrect or fluctuating DEF level readings

• DEF quality or concentration warning messages

• Check engine or SCR warning lights

• DEF sensor communication faults or diagnostic trouble codes

• Emissions-related engine power derating

• Missing or inaccurate DEF temperature information

WHY REPLACE A DEF QLS HEADER?

A malfunctioning DEF quality level sensor can prevent the vehicle's emissions control system from accurately monitoring DEF conditions.

Replacing a defective sensor with the correct Genuine OEM International 4097728C91 DEF QLS Header helps restore intended fluid monitoring and communication with the SCR system.

Proper DEF sensor operation supports accurate emissions diagnostics, reliable DEF level reporting, and the correct operation of the vehicle's emissions control strategy.

FITMENT INFORMATION

The International 4097728C91 DEF QLS Header requires careful verification of the original DEF tank and emissions system configuration.

Before purchasing, confirm:

• Original OEM Part Number: 4097728C91

• DEF Tank Capacity: 10.6, 15.9, or 25.2 Gallons

• Truck make, model, and model year

• Federal emissions year and SCR system configuration

• DEF sensor generation and calibration

• Sensor length and tank depth

• Electrical connector and wiring configuration

• Tank mounting interface

• DEF fluid line and coolant connection arrangement

• Vehicle Identification Number (VIN)

If you are unsure whether this DEF header fits your truck, please contact us with your VIN, truck model, model year, DEF tank capacity, and original part number before ordering.

Installation Note: DEF header replacement should follow International / Navistar service procedures. Prevent contamination of the DEF system, verify all electrical and fluid connections, and check sensor communication and SCR system operation after installation.

GENUINE INTERNATIONAL PART

International / Navistar supplies replacement components for commercial diesel vehicles and emissions control systems.

The Genuine OEM International 4097728C91 DEF QLS Header is intended for compatible DEF tank applications, helping maintain accurate DEF monitoring and proper SCR system operation when correctly matched and installed.