What a DEF Delete Kit Is
DEF (diesel exhaust fluid) is a urea solution. The SCR (selective catalytic reduction) system injects it into the exhaust ahead of a catalyst to reduce NOx. Monitoring sensors sit upstream and downstream of that catalyst.
A DEF delete kit is a set of hardware, plus the tuning that goes with it, that removes the SCR section from the exhaust path of a dedicated off-road or competition truck. The hardware is the physical side. The tune is the software side.
Why the Tune Matters
Manufacturers build SCR systems to warn the driver when DEF is low or the system has a fault, and then to reduce engine performance if the problem is not fixed. EPA guidance for heavy-duty SCR systems describes this approach: driver warnings first, then performance reduction.
The same logic is why hardware alone does not work. The ECM watches the SCR system. If the SCR hardware is removed without a matching calibration, the truck will set codes and can reduce power. A DEF delete needs the hardware and a compatible tune together. If a kit is hardware only, you still need a compatible tuner to finish the job. See our DEF delete kit collection for what is currently listed.
Does a DEF Delete Fit My Truck?
DEF and SCR design and tuning differ by engine, so fitment is platform-specific. EngineGo's DEF-related listings cover these platforms:
- 6.7L Power Stroke. EngineGo lists kits by build range: 2011 to 2014, 2015 to 2016, and 2017 to 2023. Our 6.7 Powerstroke DEF delete and tuner setup guide walks through the full setup.
- 6.7L Cummins. EngineGo's 6.7 Cummins DEF-era kits cover 2013 and newer Ram 2500 and 3500 trucks. See our 6.7 Cummins DEF delete and SCR removal guide.
- Duramax LML (2011 to 2016) and L5P (2017 and newer). Both run DEF. The LML exhaust also has a fitment split at 2015.5, so check your build date. The L5P has its own tuning requirements, so confirm the tuner supports your truck before you order.
Earlier engines without SCR do not need a DEF delete. The 2007.5 to 2010 LMM Duramax, for example, has a DPF and EGR but no DEF system.
Before ordering, confirm your VIN, build date, cab configuration, and bed length. If you are unsure, send them to us.
DEF Delete Alone or a Full Setup?
The DEF system is separate from the EGR and DPF systems, but the three share sensors and calibration. If you plan to work on more than one on an off-road truck, tell us before you order so the hardware and the tune match the final configuration. A tune built for a partial setup can need reworking when you add the rest.
Our pros and cons of diesel delete kits guide covers the trade-offs.
Is a DEF Delete Legal?
Not for on-road use. Removing or disabling emissions equipment on a vehicle used on public roads violates the federal Clean Air Act and many state laws. An off-road use disclaimer does not change how an EPA-certified vehicle is treated under federal law. Check federal, state, and local rules for your situation before buying or installing anything.
FAQs
Does a DEF delete require a tune?
Yes. Without a compatible tune, the truck will set codes and can reduce power. Hardware alone is not enough.
Can I leave the DEF tank installed?
That depends on the platform and the kit. Check the product page for what your specific kit requires, or ask us.
Which platforms do you cover?
6.7L Power Stroke, 6.7L Cummins, and Duramax LML and L5P. Match your engine and model year on the collection pages above, or send us your VIN.
Should I do just the DEF, or more?
That depends on your truck and what is actually failing. Diagnose first, and talk to us about the configuration before you order.
Shipping and Returns
Most orders are processed the same or next business day, excluding Sundays, unless otherwise stated. Most packages are delivered within 3 to 5 business days after leaving the warehouse, depending on package size, location, and carrier conditions.
Returns are accepted within 45 calendar days of delivery on unused, uninstalled parts in original condition with all included hardware. Installed, modified, or damaged parts may not be returnable. Electronic parts and tuners may have stricter return limits, and kits that include a tuner may differ. Return shipping may be the customer's responsibility on returns for buyer's reasons. Contact us for an RMA before shipping anything back.
Next Step
Send us your VIN, build date, and whether the truck is a dedicated off-road build. We will confirm which kit and tuner fit before you order.
