This article was adapted for drivers and tuning professionals in the United States by Viezu USA. Measurements are shown in US units alongside the originals.
Work on commercial vehicles and haven't installed KESS3's latest update yet? You're missing a lot. Alientech's 2.21 release adds BOOT mode protocols for the ACMs in some of the most common trucks on the road, a significant upgrade for tuning professionals.
Here's what changed, why it matters and how it can add real value to your business.
Inside Alientech KESS3 Update 2.21
The update brings full BOOT mode access to:
- Continental CM1881 ACMs, used in DAF, Peterbilt, Youtong and Kenworth trucks with 10.8L and 12.9L Paccar engines
- Scania EEC3 ACMs, found in the 16.4L V8 Scania R-Series built from 2013 onward
BOOT mode talks directly to the module's memory. Rather than reading and writing through the diagnostic port, you get complete access on the bench, making deeper repairs, tuning and customization possible that used to be out of reach or needed costly third-party services.
Newly Supported Vehicles at a Glance
- DAF: Paccar 10.8L and 12.9L
- Peterbilt: Paccar 10.8L and 12.9L
- Youtong: Paccar 10.8L and 12.9L
- Kenworth: Paccar 10.8L and 12.9L
- Scania R-Series: 16.4L V8 (EEC3)
These are high-demand trucks with complex aftertreatment systems, so being able to program or repair ACMs in-house is a real advantage for any tuner or shop in this sector.
BOOT Mode Explained, and Why It's Worth Using
BOOT mode connects you directly to the control unit's board for low-level data access. It's a hands-on, bench-based process that gets past the software protections and limits you'd hit over OBD.
Why that matters:
- You can clone modules for replacement
- You can recover bricked ECUs or ACMs
- You can customize regen behavior and aftertreatment settings
- You have full flexibility for fault-finding or performance tuning
That level of access means fewer limits, more control, and the ability to take on complex jobs other tuners might turn away. Watch the video
What the Update Means for Your Business
Small shop or growing operation, full BOOT access to ACMs opens new services that keep customers returning:
- Less downtime: you fix problems quickly, and customers love that
- No outsourcing: keep the control, and the margin, in-house
- Offer what others can't: stand out on technical ability
- More dependable fixes: deeper access means better diagnostics and tuning
We've seen again and again at Viezu how adopting the newest protocols and tools gives businesses a real edge, in what they can do and in how confident they feel doing it.
Getting KESS3 Tools and Training
Want to make the most of this update? We can help. As official Alientech distributors, we don't just sell hardware; we train you to use it properly, from initial setup through ongoing training and support. Best of all, our KESS3 tool training is completely free through the Viezu Technical Academy.
- Get your KESS3 tool or adapter kits from Viezu
- Book a hands-on, expert-led Remap101 course for real experience with BOOT mode, ACM tuning and more
We support beginners and experienced tuners alike, with courses built around real jobs rather than theory.
FAQs
What is BOOT mode, exactly?
A way of accessing an ECU or ACM by connecting physically to its board, getting past software locks to reach the memory directly. It's especially useful when the unit can't be programmed through the diagnostic port.
Is BOOT tuning risky? Could it damage a module?
Done correctly, it's safe, but it's not something to try without training: one slip with a probe can damage the board. That's why we offer hands-on training at Remap101.
Do I need new hardware for these protocols?
Most KESS3 users already have what they need, plus the right probe adapters and a solid bench setup. Not sure? Contact the Viezu team and we'll talk you through it.
Is there demand for ACM work in the US?
Yes, and it's growing. Fleets are under pressure to stay compliant and keep trucks running, so ACM faults are increasingly common, and shops that can fix them in-house are solving a real problem.
What can I actually do with ACM access?
Everything from fault diagnosis and regen problems to component matching and module cloning. You can also adapt aftertreatment behavior for off-road or motorsport use, depending on your customer's needs and local laws.
US emissions compliance note
In the United States, modifying, removing or disabling emissions-control equipment (including DPF*, EGR*, SCR*/DEF* and catalytic converter systems) on a vehicle used on public roads may violate the federal Clean Air Act and EPA rules, and in California and other states that follow CARB standards, additional restrictions apply. Any off-road, race or competition-only modification described here is not intended for street use. Nothing in this article claims that any product or calibration is EPA- or CARB-certified or street legal. For guidance on options for your vehicle, contact Viezu USA.
Talk to Viezu USA
Want to know what Viezu can do for your vehicle or your business? Request a performance upgrade quote, browse viezuusa.com or contact the Viezu USA team.
* EMISSIONS TAMPERING WARNING
Removing, disabling, deleting, or rendering inoperative any emissions control device or system (including DPF, EGR, SCR/DEF, catalytic converters, and related sensors or software) on a vehicle used on public roads is prohibited under the U.S. Clean Air Act and may also violate state laws, including California Air Resources Board (CARB) regulations. Violations can carry substantial civil penalties for vehicle owners, installers, and sellers.
Any reference in this article to DPF, EGR, SCR, or other emissions-related functions is provided for informational purposes and, where applicable, for closed-course competition or off-road use only where permitted by law. Viezu USA does not condone emissions tampering on any road-going vehicle. It is the customer's sole responsibility to ensure that any modification complies with all applicable federal, state, and local laws, regulations, and policies, regardless of what country you live in.