4254202C91 | Genuine OEM International/Navistar DEF QLS Header 15.5G/23G

The 4254202C91 Genuine OEM International/Navistar Diesel Exhaust Fluid (DEF) QLS Header is a tank-mounted component designed for compatible DEF systems. The header assembly supports monitoring of DEF tank conditions, helping the vehicle's emissions control system operate according to its design.

PRODUCT INFORMATION

• Part Number: 4254202C91
• Brand: International / Navistar
• Condition: Genuine OEM — confirm the item's actual condition with the seller
• Component: Diesel Exhaust Fluid (DEF) QLS Header
• System: DEF / SCR Emissions System
• Tank Applications: 15.5-gallon and 23-gallon DEF tanks, subject to fitment verification

APPLICATIONS

This DEF QLS Header is listed for compatible 15.5-gallon and 23-gallon DEF tank configurations. Exact compatibility depends on the vehicle model, model year, tank capacity, electrical connections, and original part number. Verify the application before ordering, as different DEF header assemblies may not be interchangeable.

FUNCTION

The DEF QLS Header is installed in the DEF tank assembly and supports monitoring of fluid conditions, such as level, quality, and temperature, depending on the specific configuration. These signals help the vehicle's emissions control system manage diesel exhaust fluid operation.

SIGNS OF A FAULTY DEF QLS HEADER

A faulty DEF header or related system issue may cause:

• DEF level readings that are incorrect or inconsistent
• DEF quality or temperature sensor fault codes
• Check engine or emissions system warning lights
• SCR system warnings or fault messages
• DEF system performance or communication issues
• Emissions-related derate warnings on applicable vehicles

These symptoms may also result from wiring faults, contaminated DEF, connector problems, or other emissions system components. Proper diagnostics are recommended before replacing the header.

WHY REPLACE THE DEF QLS HEADER?

Replacing a confirmed faulty DEF QLS Header with the correct compatible unit can help restore accurate tank monitoring and normal DEF system operation. Depending on the vehicle, fault-code clearing, system checks, or additional diagnostic procedures may be required after installation.

FITMENT INFORMATION

Verify that part number 4254202C91 matches the original DEF header before ordering. Compatibility depends on the vehicle model year, DEF tank capacity, connector type, and system configuration. Tank capacity alone is not sufficient to confirm fitment.

If you are unsure whether this part is correct for your vehicle, please contact us with your VIN and original DEF header part number. We are happy to help verify compatibility before purchase.

GENUINE INTERNATIONAL / NAVISTAR PART

Part Number: 4254202C91