5012173R91 | Genuine OEM International/Navistar 12-Gal DEF Quality & Level Sensor Head

The 5012173R91 DEF Quality & Level Sensor Head Unit is a genuine OEM International/Navistar component designed for compatible 12-gallon diesel exhaust fluid (DEF) tank systems. It monitors DEF level and fluid quality to support proper operation of the vehicle's emissions aftertreatment system. Verify the original part number and tank configuration before ordering.

PRODUCT INFORMATION

Part Number: 5012173R91
Brand: International / Navistar
Condition: Genuine OEM — confirm the item's actual condition with the seller
Component: DEF Quality & Level Sensor Head Unit
Tank Capacity: 12 Gallons
System: Diesel Exhaust Fluid (DEF) / SCR Aftertreatment System

APPLICATIONS

Designed for compatible International/Navistar vehicles equipped with the matching 12-gallon DEF tank and sensor configuration. Exact vehicle models, engine applications, and production years should be verified before purchase.

FUNCTION

The DEF quality and level sensor head monitors the amount and quality of diesel exhaust fluid in the tank. The information is used by the vehicle's emissions control system to help manage DEF usage and aftertreatment operation.

SIGNS OF A FAULTY DEF QUALITY & LEVEL SENSOR

• Incorrect DEF level displayed on the dashboard

• DEF quality warning despite properly filled tank

• DEF system or aftertreatment warning lights

• Fault codes related to DEF level or quality

• Unexpected DEF level readings

• Emissions system performance warnings

These symptoms may also be caused by wiring, connectors, contaminated fluid, or other aftertreatment components. Proper diagnosis is recommended before replacement.

WHY REPLACE THE DEF SENSOR HEAD UNIT?

A faulty sensor can provide inaccurate DEF level or quality information and may trigger aftertreatment warnings. Replacing a confirmed defective sensor with the correct compatible unit can help restore accurate monitoring and normal DEF system operation.

FITMENT INFORMATION

Part Number: 5012173R91
Brand: International / Navistar
Component: DEF Quality & Level Sensor Head Unit
Tank Capacity: 12 Gallons

Confirm the part number, tank capacity, connector, and sensor configuration against the original unit before purchase. If you are unsure whether this part is correct for your vehicle, please contact us with your VIN and original part number. We are happy to help verify compatibility before purchase.

GENUINE INTERNATIONAL / NAVISTAR PART

Part Number: 5012173R91