Precision-Controlled Emissions: Newmar Cummins ISX DEF Head Unit
What is it?
The Newmar Cummins ISX DEF Head Unit is a vital component within the Selective Catalytic Reduction (SCR) system on Newmar motorhomes equipped with Cummins ISX engines. This unit manages the delivery and monitoring of Diesel Exhaust Fluid (DEF), ensuring accurate dosing into the exhaust stream to neutralize harmful nitrogen oxides (NOx). Integrated sensors track DEF level, temperature, and pressure for reliable emissions compliance and system feedback.
Why choose a Newmar-specific DEF Head Unit?
Engineered for seamless integration into Newmar coach platforms powered by Cummins ISX engines, this DEF Head Unit ensures optimal system communication and function from the factory configuration. It eliminates the need for adaptations or retrofits, reducing the risk of SCR faults, limp-mode events, and emission test failures. Direct-fit design means you can rely on OEM accuracy and longevity.
Key Benefits
✅ Purpose-built for Newmar motorhomes with Cummins ISX engines
✅ Precisely regulates DEF injection for maximum NOx reduction
✅ Monitors fluid temperature, level, and pressure via built-in sensors
✅ Designed to resist DEF crystallization, temperature extremes, and corrosion
✅ Helps prevent SCR-related faults, EGR derates, and emissions system failures
Applications
Ideal for Newmar motorhomes powered by Cummins ISX diesel engines, this DEF Head Unit supports reliable emissions performance across travel, duty, and idle cycles. It’s essential for operators who demand clean, compliant operation without sacrificing drivetrain reliability or passenger comfort.
Installation Notes
Before replacing, drain or bypass existing DEF fluid and isolate electrical power to the system. Clean the DEF tank and surrounding fittings to remove residue or crystallized deposits. Install the new unit with OEM connectors and fasteners, ensuring sensors are aligned and fluid lines are properly sealed. After installation, clear active DEF system codes, prime the system if needed, and verify dosing and sensor readings with a diagnostic scan tool.
Final Thoughts
If your Newmar motorhome is exhibiting DEF system error codes or failing emissions diagnostics, the proper DEF Head Unit is the fix. This OEM-grade unit ensures your Cummins ISX engine remains road-legal and reliable. Available at Tamerx for fast shipping and backed by trusted parts expertise.