How we work, what we guarantee, and where you stand

1 · What we sell

We sell two things, and they follow different rules:

• Remote engine services — tuning, calibration, diagnostics, parameter and configuration work carried out on your engine control unit over a remote session, normally TeamViewer. We connect to your laptop; your laptop stays connected to the engine.
• Software services — installing, licensing help and configuring the diagnostic and calibration software you already work with, plus tools we publish ourselves.

Nothing is shipped. There are no physical parts, no hardware and no courier. If a job needs a datalink adapter, a cable or a laptop, those are yours to provide — see section 7.

2 · How a remote job runs

Step 1 — You tell us the engine

Order the service and give us the ESN or VIN at checkout, plus the truck or machine and what it is doing. Those two lines are what let us answer honestly instead of guessing.

Step 2 — We check the engine before we start

We look up the calibration and confirm the work is possible on your exact ECU and software level before any work begins. If it is not possible, we say so and refund you in full — see section 4. We would rather lose the order than take money for a job we cannot finish.

Step 3 — We agree a time

We reply by email to arrange the session. Sessions run at a time that suits your workshop, including outside normal hours for a truck that is down. Rescheduling costs nothing; just tell us as early as you can.

Step 4 — The session

You start the remote session and stay with the vehicle. A typical job takes 30 to 90 minutes. Before we change anything we read and keep a copy of the calibration currently in the ECU, so there is always something to go back to.

Step 5 — Completion

The job is complete when the agreed work has been written to the ECU and checked. We tell you what changed and what to watch for.

Step 6 — After

Your order page keeps the record. If something is not right, the warranty in section 3 applies — you do not pay twice to have our own work corrected.

3 · Warranty

Tuning & calibration — for the life of the ECM

There is no 30-day clock and no expiry date. A calibration we wrote is covered for as long as the control module we wrote it to keeps running. If it stops behaving as agreed, we put it right at no charge — this year or in five years.

• Free revisions, no limit. Driveability, a parameter that needs trimming, a fault traceable to our work — we adjust it, as many sessions as it takes.
• Free restore. We keep the calibration we read out before touching anything, and will write it back whenever you ask, for any reason.
• Support with no time limit on a job we did.

Three things end that cover

1. The ECM fails. A calibration lives inside one specific control module. When that module dies, our work dies with it — there is nothing left to warrant. Fitting a replacement module is a new job at the full price: the new one has to be read, matched and written from scratch.
2. The ECM is updated or reflashed without us. A dealer update, a service-tool reflash, another shop — any of them overwrite what we wrote, and the calibration is gone. Putting it back is a new order, charged as a new job, not a warranty claim. If you are not sure whether an update will overwrite our work, ask first: one email is cheaper than a second job.
3. The work is shared. Everything we deliver carries markers unique to your account — see section 5. If our work turns up somewhere it was not sold, the warranty ends that day, and so does the account.

Software services — 6 months

Installation, licensing and configuration work is warranted for six months. Inside that period we put right anything that stops working through no fault of yours, free of charge. The warranty holds on one condition: the machine is left as we set it up.

• Do not let Windows update itself. If we deferred or disabled updates, that was deliberate. An operating-system update is the single most common way a working diagnostic installation dies overnight, and it usually takes the licence activation with it. A machine that has updated itself falls outside the warranty and the reinstall is chargeable.
• Do not update the diagnostic software yourself. A publisher’s update can replace the very components the installation depends on. Tell us what you need and we will do it properly; click Update on your own and the six months stop there.
• One installation, one machine. Moving to another PC, replacing the drive or reinstalling Windows means a new activation and a new order.
• Leave the components in place. An antivirus that quarantines part of the install, a “cleaner” tool, or a pirated operating system all void the warranty — none of those are things we can work against.

What neither warranty covers

• Mechanical, electrical or aftertreatment faults that existed before the session, or that develop independently of our work — a worn injector, a failed sensor, a wiring fault, a blocked filter.
• Damage from a session interrupted at your end: power lost during a write, an adapter unplugged, the internet dropping. This is exactly why we insist on a battery charger and a stable connection in section 7.
• Fuel economy, power output or emissions figures. Results depend on engine condition, load, fuel and how the machine is worked, so we do not warrant numbers.
• Any machine where the information you gave us — the ESN or VIN — was not the machine we actually worked on.

To claim, email info@vietdiesel.com with your order number and what the machine is doing. There is no form to fill in and no window to miss.

4 · Refunds & cancellations

Before the session — full refund

Cancel at any point before the remote session starts and you get 100% back: no reason needed, no fee, no argument. That includes the case where our engine check (step 2) shows the job is not possible on your ECU — there we refund without waiting for you to ask.

Rescheduling — free

Book another time, as often as you need. We only treat an order as abandoned if we cannot reach you for 30 days, and even then we refund on request.

Once the session ends — no refund

This is a digital service. When the remote session closes the work has been delivered: the calibration is in your ECM, the software is on your machine, the knowledge is yours to keep. None of that can be handed back, so no refund is issued after a session has been completed — and that is exactly why the warranty above carries no 30-day clock. You are not left without recourse; you are left with cover that outlasts any refund window.

We do still refund, at any stage, if:

• you were charged twice or charged in error;
• we could not deliver the service we sold you;
• we caused damage we cannot put right — and there, a refund is not the limit of what we will discuss with you.

Chargebacks

A chargeback or a payment dispute is not a refund route for a service that was delivered. We keep the order, the acceptance you ticked at checkout, the engine details you supplied and the record of what was written and when — and we submit all of it. Opening a dispute instead of talking to us closes the account and ends every warranty on it. Tell us the problem first; nine times out of ten it is fixed in the next session.

Refunds that are due go back through PayPal to the account that paid, normally within 5 business days. Where consumer law gives you a right to cancel that is stronger than this policy, that right applies and nothing here removes it.

5 · Licensing, traceability & account termination

Everything we deliver is marked

Files, calibrations and tools that leave this workshop carry identifiers unique to the account that bought them, embedded in the data itself. They survive copying, renaming, re-packing and being flashed into another module. When something of ours turns up where it was not sold, we are not guessing about where it came from — we can read it.

What your licence allows

• One job, one ECM. A calibration is licensed for the single control module it was written to. A workshop ordering for its own customer’s truck is exactly that — one engine — and is entirely fine.
• Tools we publish are licensed to one workshop and activated per machine. Your own technicians may use them; nobody else may.
• Your account login is yours. Sharing it counts as sharing everything behind it.

What ends the relationship

Passing on, reselling, publishing or uploading anything we supplied — to a colleague, a forum, a file-sharing site, a cloud drive or a chat group — re-using a calibration on a second machine, or reverse-engineering our tools. If we find it:

• Every warranty on the account ends immediately, including lifetime cover on work already done.
• The account is closed and its licences revoked. No refund is due for anything, including work not yet delivered.
• You do not buy from us again — under that name or any other.
• We reserve the right to recover our losses, calculated at the full commercial price of every copy traced back to the account.

Giving false information to obtain a cheaper job — the wrong ESN, someone else’s machine, a licence claimed but not held — ends the same way: the order is cancelled, nothing is refunded, and the account is closed.

Third-party software

• We sell the service, not the publisher’s licence. When you order an installation or configuration service you are paying us for our time and expertise. The software stays the property of its publisher and is governed by that publisher’s own licence, which is between you and them.
• You must be entitled to the software. By ordering, you confirm you hold, or are entitled to hold, a valid licence for anything we help you install.

6 · Prices, payment & invoices

• All prices are in US dollars. The price shown when you order is the price you pay; we do not add fees afterwards.
• Payment is handled by PayPal, using your PayPal balance or any card PayPal accepts. The card details are entered on PayPal’s own page — we never see or store them, and nothing sensitive touches our servers.
• Your payment is covered by PayPal Buyer Protection under PayPal’s terms, in addition to the rights this page gives you.
• An invoice PDF is issued for every order and stays in your account. The billing details you enter at checkout are what appear on it, so put your company name and tax number in if you need them there.
• Any taxes or duties payable in your own country are your responsibility. Quoted prices do not include them.

7 · Your responsibilities

• Accurate engine details. The ESN or VIN you give us must be the engine we will be working on. Work carried out on the wrong information is not covered by the warranty.
• A Windows laptop with the relevant OEM diagnostic software installed and working, plus a compatible datalink adapter and cable connected to the vehicle. If you are not sure what you need, ask before you order.
• A battery charger or maintainer on the vehicle. Voltage dropping during a write is the one failure that can genuinely hurt an ECU. We may refuse to start without one.
• A stable internet connection at the vehicle, and someone present at the machine for the whole session.
• The right to work on the vehicle. You confirm you own it or are authorised by the owner, and that you are legally able to enter this agreement.

8 · Intended use & compliance

Our tuning and calibration services are supplied for off-road, competition, motorsport, agricultural, marine, research and export applications, in markets where such use is permitted.

• You decide, before you order, whether a change is legal to make and to operate where you are. Rules differ by country, state and by how the machine is used, and only you know how yours will be used.
• We make no representation that any calibration is approved or legal for use on public roads in any particular jurisdiction, and we do not certify compliance with any emissions standard.
• Work should be carried out by, or under the supervision of, a qualified technician. Engine and aftertreatment systems are unforgiving of guesswork.
• We may decline or cancel any order, at our discretion, if the intended use is unclear, misrepresented or unlawful. If we decline, you are refunded in full.

9 · Risk & limits of liability

Working on an ECU carries risk, and we would rather set it out plainly than bury it. We reduce that risk the way a careful workshop does: we check the engine first, we keep a copy of what was in the ECU before we touched it, and we insist on stable power.

Subject to the warranty in section 3, and to the maximum extent permitted by law, VietDiesel’s total liability for any claim connected with an order is limited to the amount you paid for that order. We are not liable for indirect or consequential losses — lost work, downtime, towing, lost contracts, or a machine being off the road.

Nothing on this page excludes or limits liability for death or personal injury caused by negligence, for fraud, or for anything else that cannot lawfully be excluded. Where consumer law in your country gives you rights that are stronger than this section, those rights apply.

10 · Privacy

What we collect

• Contact and billing details — name, email, phone, company, tax number and address, because an invoice needs them.
• Engine and job data — the ESN or VIN, the machine, your notes, the calibration read from the ECU, and what we changed. This is what makes the warranty and the free restore possible.
• Order history, and basic technical data such as your IP address when you use the site.

What we do not collect

Card and bank details never reach us — PayPal handles payment on its own pages. We do not record remote sessions unless you ask us to and agree in writing, and the remote-access tool runs under your control on your laptop: you start it, and you can end it at any moment.

Why we hold it, and for how long

To do the work, to support it afterwards, to honour the warranty, and to meet tax and accounting law. Order and invoice records are kept as long as that law requires. Calibration reads are kept for 12 months so we can put your engine back the way it was; tell us to delete yours sooner and we will.

Sharing

We share data with our payment processor to take payment and with our email provider to reach you, and otherwise only where the law requires it. We do not sell your data, and we do not share your engine data with anyone.

Your rights

Write to info@vietdiesel.com to see what we hold, correct it, delete it, get a copy, or object to how we use it. We answer within 30 days. Rights and timescales follow the data-protection law that applies to you — the GDPR, for example, where it does.

Cookies

We use essential cookies to keep you signed in and to remember your cart. Anything beyond that is optional and you can decline it without losing any part of the site.

11 · Support, complaints & law

One address reaches a person who can act on it: info@vietdiesel.com. Include your order number and we will not ask you to repeat yourself. Urgent cases — a truck down, a derate, a machine that will not start — go to the front of the queue at any hour.

If we have got something wrong, tell us before you tell PayPal: we would rather fix it than argue about it, and a claim takes far longer than a phone call. If we still cannot agree, these terms are governed by the law of Vietnam, and the courts there have jurisdiction — without removing any right you have to bring a claim where you live.

We may update this page as the service changes. The date at the top is the version in force; the terms that apply to your order are the ones published when you placed it.