Peterbuilt/ Kenworth Cummins X15 DEF Sensor

Precision DEF Quality Monitoring for Peterbilt/Kenworth: OEM Q21-6170-002K1T

What is it?
The OEM part Q21-6170-002K1T is a Diesel Exhaust Fluid (DEF) level and concentration sensor designed for use in heavy-duty trucks such as Peterbilt and Kenworth equipped with Cummins engines. It accurately measures the amount and quality of DEF in the tank, allowing the SCR (Selective Catalytic Reduction) system to adjust dosing and maintain emissions compliance. 

Why Choose the OEM Q21-6170-002K1T Sensor?
This sensor is manufactured to meet the original equipment standards of PACCAR (the parent of Peterbilt and Kenworth), meaning the mounting geometry, electrical connector, and sensing capabilities match the factory-installed version. By installing a correct-spec sensor, you reduce the risk of DEF system faults, incorrect dosing, or emissions derates. 

Key Benefits
✅ Factory-Correct Fitment: Designed to match the original layout for seamless installation.
✅ Heavy-Duty Design: Built to handle DEF fluid exposure, vibration and harsh conditions.
✅ Accurate DEF Monitoring: Measures both fluid level and concentration to support proper SCR performance. 
✅ Performance Stability: Supports correct sensor feedback, reducing fault codes or unexpected derates.
✅ Emissions System Protection: Ensures the rest of the after-treatment system (SCR catalyst, sensors, dosing system) works efficiently.

Applications
This sensor is ideal for Peterbilt and Kenworth trucks using Cummins X15 (or similarly specified) engines with SCR/DEF systems that require the OEM Q21-6170-002K1T sensor. It suits fleet, long-haul, regional and vocational applications where proper DEF system function is essential.

Installation Notes
Installation should be done by a qualified technician. Begin by verifying that the part number matches the original sensor and your vehicle’s configuration. Disconnect the battery, relieve any pressure in the DEF system, and remove the old sensor assembly. Clean the mounting area and inspect for DEF crystallization or corrosion. Install the new sensor, ensuring proper orientation, seal integrity and connector engagement. Reconnect wiring, clear any diagnostic trouble codes, and perform a system check verifying DEF level and concentration readings. Proper installation helps ensure reliable SCR operation and emission system performance.

Final Thoughts
In modern heavy-duty diesel emissions systems, accurate DEF monitoring is essential. The OEM Q21-6170-002K1T sensor provides a factory-matched, reliable solution that helps your Peterbilt or Kenworth truck’s SCR system operate correctly, minimizing downtime and supporting compliance for mile after mile.