4254201C91 | Genuine International® / Navistar® 9.5 Gallon DEF Tank QLS Sensor Head

The 4254201C91 QLS Sensor Head is designed for compatible International® / Navistar® Diesel Exhaust Fluid (DEF) tank systems. Intended for a 9.5-gallon DEF tank application, this component is associated with DEF quality-level sensing within the vehicle's emissions control system. Verify the original part number and tank configuration before ordering.

PRODUCT INFORMATION

Part Number: 4254201C91
Brand: International® / Navistar®
Condition: Genuine OEM
Component: DEF Tank QLS Sensor Head
System: Diesel Exhaust Fluid (DEF) / Selective Catalytic Reduction (SCR)
Tank Capacity: 9.5 gallons
Sensor Type: QLS (Quality Level Sensor)

APPLICATIONS

Designed for compatible International® / Navistar® DEF tank configurations with a 9.5-gallon capacity. Exact fitment depends on vehicle model, model year, tank configuration, electrical connector, and original equipment part number.
Confirm compatibility using the vehicle VIN and the part number on the existing sensor head before purchase.

FUNCTION

The QLS sensor head works with the DEF tank monitoring system to provide information related to DEF quality and tank conditions, depending on the system configuration. Its readings help the vehicle's emissions control system monitor DEF and support proper SCR system operation.

COMMON SIGNS OF FAILURE

• DEF quality sensor fault codes
• Incorrect or inconsistent DEF system readings
• Check Engine Light or emissions system warnings
• SCR system warning messages
• DEF sensor communication problems
• Emissions-related warnings or engine derate conditions

WHY REPLACE THE QLS SENSOR HEAD?

A faulty QLS sensor head can cause inaccurate DEF monitoring, diagnostic trouble codes, and emissions system warnings. Replacing a confirmed defective component with the correct compatible part can help restore reliable DEF system monitoring.

FITMENT INFORMATION

Before ordering, verify part number 4254201C91, the 9.5-gallon tank application, connector configuration, and vehicle compatibility against the original component or an OEM parts catalog. Do not assume that this sensor head fits every International® / Navistar® DEF tank.

GENUINE INTERNATIONAL PART

Part Number: 4254201C91