Oxbo DEF, DPF & EGR Delete and Tuning: What Owners Need to Know
September 14, 2026
Liebherr DEF Delete & Tuning: What Owners Need to Know
If you run a Liebherr excavator, wheel loader, dozer, material handler, harbour crane, or mining machine, you know what downtime costs. A DEF or SCR fault often has nothing to do with the health of the engine. The machine still runs mechanically fine, but the aftertreatment system has put it into a warning, a limited mode, or a full derate.
TM AG Tuning works with diesel agricultural, construction, forestry, and heavy equipment. For supported Liebherr machines, that includes ECU calibration for the DEF / SCR system where an emissions modification is legally permitted for the machine’s intended use.
How Liebherr work is done: the ECU is shipped to us by UPS so we can open it on the bench. We send you the shipping labels, and the whole trip usually takes about 7 days: about 3 days to reach us and about 3 days to get back to you. We currently support ECU2 and ECU2HD controllers only. To get started, select your machine on our Make and Model Search page.
What Is DEF on Liebherr Equipment?
DEF stands for Diesel Exhaust Fluid. It is a urea-based solution stored in its own tank, and it never goes into the engine. Instead, it is sprayed into the exhaust as part of the Selective Catalytic Reduction system, usually called SCR.
In the hot exhaust, DEF lets the SCR catalyst turn nitrogen oxides (NOx) into mostly nitrogen and water. The whole DEF / SCR system exists to cut the NOx coming out of the exhaust.
The system is a lot more than a tank. Depending on the engine and machine, it can include:
- The DEF tank, tank heater, and level and quality sensors
- A pump or supply module and DEF lines
- A DEF injector (doser)
- NOx sensors and exhaust temperature sensors
- The SCR catalyst
- Control logic in the engine ECU or a separate aftertreatment controller
That is why a “DEF fault” on the display does not automatically mean the fluid is bad. The real problem can be the doser, a heater, a sensor, wiring, catalyst efficiency, or communication between controllers.
Common DEF and SCR Problems
Liebherr machines work in dust, mud, cold starts, short cycles, and long high-load days, and the aftertreatment system lives in the same conditions. Common failures involve DEF pressure, DEF quality readings, tank heaters, dosers, pumps, NOx sensors, wiring, and SCR efficiency.
The frustrating part is that the engine can sound and feel healthy while software holds the machine back. The ECU monitors emissions performance constantly, so an SCR fault can trigger warning lights, fault codes, and on many systems an eventual power or speed derate. A sensor problem becomes a machine that cannot dig, load, or travel normally.
DEF vs. DPF vs. EGR
These three systems do different jobs, even though people often call all of them “the emissions system.”
- EGR sends some exhaust back into the intake to lower combustion temperature and reduce NOx.
- DPF traps soot in the exhaust and burns it off during regeneration.
- DEF / SCR sprays Diesel Exhaust Fluid into the exhaust so the SCR catalyst can reduce NOx.
Many engines use more than one. Replacing a DPF will not fix a failed DEF pump, and clearing a NOx code will not free a stuck EGR valve, so correct diagnosis still matters. This page covers DEF / SCR on supported Liebherr ECUs.
Why Owners Remove DEF, and What Changes
The main reason is uptime, not horsepower. Quarry, demolition, port, and mining schedules do not wait for a dealer parts delay. When a large excavator, XPower loader, or harbour crane is tied to trucks, crushers, or a vessel, an aftertreatment derate can stop the whole job.
Where it is legally permitted for the machine’s use, and the SCR strategy is removed and calibrated correctly, owners typically see these changes:
- Fewer failure points. The machine no longer needs DEF dosing to stay out of derate, so dosing, quality, heater, and SCR efficiency faults stop being a reason for downtime. A sensor is rarely the expensive part of a breakdown; the lost production hours are.
- No more DEF. With SCR fully removed from the operating strategy, the machine no longer uses DEF. That also ends problems with frozen, contaminated, or poor-quality fluid.
- A way out of repeat derates. Machines that keep dropping back into derate after faults are cleared are usually what brings owners to us.
We do not promise a horsepower number or a fuel-savings percentage. Fuel use and power depend on load, site conditions, the operator, and the rest of the calibration. A DEF calibration can keep factory-like power, and a separate performance calibration is a different job that only makes sense for some machines. An emissions calibration also does not fix an unrelated fuel, turbo, electrical, hydraulic, or mechanical problem.
How Liebherr ECU Tuning Works at TM AG Tuning
Liebherr work is not a remote flash. The ECU comes to our shop.
- Select your machine. Choose your Liebherr on our Make and Model Search page. That opens a ticket with our support team.
- Support replies with what needs to be done. We confirm that your machine has a supported ECU2 or ECU2HD controller and walk you through the next steps.
- We send you UPS shipping labels. You remove the ECU, pack it, and send it with the label we provide. Transit to us usually takes about 3 days.
- We open and calibrate the ECU on the bench. We read it and build the calibration for the scope we agreed on. We aim to finish within 48 hours of receiving the ECU.
- We ship it back by UPS. The return trip usually takes about 3 days, so the whole process is typically about 7 days.
- You reinstall and check operation. If anything still is not right, reply on your support ticket.
You do not need to know which ECU your machine has before you start. Support confirms it after you submit your machine. A solution for one Liebherr model does not automatically apply to another, because engines, software versions, and aftertreatment layouts vary even within one product family.
For a comparison with our remote jobs, see How Remote Tuning Works for Agricultural and Construction Equipment.
Supported Liebherr Models (ECU2 / ECU2HD)
We can work on these models when the machine has an ECU2 or ECU2HD controller. Our support team confirms your controller before anything ships.
Crawler excavators (R series): R 922, R 924, R 926, R 930, R 934, R 936, R 938, R 945, R 950, R 956, R 960, R 960 SME, R 960 Demolition, R 966, R 970, R 972, R 976, R 978 SME, R 980 Demolition, R 992
Wheeled excavators (A series): A 922, A 924, A 930
Wheel loaders (XPower): L 550 XPower, L 556 XPower, L 566 XPower, L 576 XPower, L 580 XPower, L 586 XPower
Crawler loaders (LR): LR 626, LR 636
Crawler dozers (PR): PR 736, PR 746, PR 756, PR 766
Material handlers (LH): LH 18, LH 22, LH 24, LH 26, LH 30, LH 35, LH 40, LH 50, LH 60, LH 80, LH 110, LH 150
Mobile harbour cranes (LHM): LHM 120, LHM 180, LHM 280, LHM 420, LHM 550, LHM 600, LHM 800
Mining excavators (R 9000 series): R 9100, R 9150, R 9200, R 9250, R 9300, R 9350, R 9400, R 9600, R 9800
Mining trucks (T series): T 264, T 274, T 284
If your machine is on this list but has a controller other than ECU2 or ECU2HD, we cannot do it under our current service. Submit it on the search page anyway, and support will tell you plainly what is possible.
Liebherr DEF Delete: Frequently Asked Questions
Can Liebherr DEF tuning be done remotely? Not currently. For Liebherr ECU2 and ECU2HD controllers, the ECU has to be shipped to us so we can open it on the bench.
How long does the process take? Usually about 7 days in total. Shipping to us by UPS takes about 3 days, we aim to finish the ECU within 48 hours of receiving it, and the return trip takes about 3 days.
Who handles shipping? We send you UPS shipping labels. You pack the ECU and ship it with the label, and we send it back by UPS.
How do I know if my Liebherr has an ECU2 or ECU2HD? You do not have to figure it out yourself. Select your machine on our search page, and support will confirm the controller before you ship anything.
Does a DEF warning mean my fluid is bad? Not necessarily. DEF warnings can come from the doser, pump, heater, NOx sensors, wiring, or catalyst efficiency, not just the fluid.
Will a DEF delete stop my Liebherr from derating? It removes DEF and SCR faults as a cause of derate. It will not fix a derate caused by an unrelated engine, fuel, hydraulic, or electrical problem, which is why support reviews your machine before any work starts. For general derate steps, see What to Do When Your Tractor or Skid Steer Is Derated.
Why Professional Calibration Matters
A modern diesel ECU does not have a simple “DEF off” switch. Torque limits, monitoring, derate logic, and communication with other controllers are all tied together in the software. A poor calibration can leave warning lights, uneven power delivery, communication faults, or service problems down the road.
Doing it properly means identifying the exact ECU hardware and software, opening the unit correctly on the bench, and building a calibration that fits the machine’s hardware and how it is used.
🛠️ Why Choose TM AG Tuning?
- ✔ Industry-leading Mitsubishi Fuso tuning
- ✔ Proven solutions for 4M50 and 4P10 engines
- ✔ Lifetime file support
- ✔ Real customer support (not just files)
We don’t just tune trucks—we fix the problems other tuners leave behind.
💬 Stop Dealing With Emissions Problems
If your Liebherr Equipment is constantly throwing DEF codes, or going into derate, it’s time for a permanent solution.
TM AG Tuning delivers reliable, powerful, and clean-running trucks without the headaches.
