Most people do not need to know how ECU work happens. They need to know the process is predictable: what gets sent, what gets done, what it involves, and when it is done. This page is that process — the way DiagAutoClinic works for owners and workshops in every province.
Why mail-in at all
A module that genuinely needs bench work cannot be fixed by another scan tool. The vehicle is a network — and when the fault is inside a module, the answer is controlled bench access: stable power, direct communication, EEPROM and flash read/write where the platform supports it. That work happens here, in one workshop, for the whole country.
The four steps
Every mail-in job follows the same sequence. Nothing is removed from your vehicle until step one is done.
- Send the VIN first. Before anything is removed, WhatsApp the VIN, vehicle year and a clear fault description. DAC confirms whether the platform is supported, whether the fault pattern points to the module or to wiring/power, and what the work will involve. Do not remove the module until we say go.
- Remove and ship. Once confirmed, remove the module. Packing instructions are provided — rigid box, bubble wrap, fragile label. We can arrange courier collection or you ship with any major courier. Send the tracking number; nothing starts until the module arrives safely.
- Bench work. The module is logged in, powered on a controlled bench supply, and backed up before anything is touched. The scope and terms are confirmed before work starts. You get WhatsApp updates, and for repairs a video call confirmation before any balance is requested.
- Return and install. The module comes back by courier with fitting notes. You install it, clear codes or run adaptations where required, and drive. Balance is due only after the work is proven.
What to send in the box
- Your name and phone number
- The return address the module must ship back to
- Vehicle make, model and year — VIN recommended
- Full fault code list if you have one
- Photos of the module label and part numbers
- Anything DAC asked for after the VIN check
How payment works
- Written quote first — you approve the scope and terms before any work starts.
- Balance only after proof — for repairs, you see the module responding before the balance is due. No payment on faith.
- Courier — return shipping is arranged per job; we can arrange collection on request.
- Digital-only dump work (no courier at all) is handled on the e-dump service.
Which modules travel well
Mail-in works for anything you can remove and courier safely. The most common are:
- ECU / ECM — engine control modules, bench read/write and recovery
- TCU / gearbox mechatronic — the electronic plate is light, which makes it one of the lightest modules to courier
- BCM / body control and cluster modules
- Immobiliser modules — EWS, CAS, FEM, EIS (with proof of ownership and signed agreements)
Platform support has hard year limits based on current tooling (VAG pre-2022, BMW and Mercedes pre-2021, Toyota pre-2022, Ford pre-2020). Send the VIN and year — if your platform is outside that range, we say so before you remove anything.
Send the VIN first
Everything starts with the VIN. It takes thirty seconds, and it is what lets us confirm feasibility before you spend a cent on courier costs or removal. No surprises, no wasted trips.
Ready to send a module in?
Start with the VIN.
Nothing leaves your vehicle until we confirm it is a mail-in candidate and quote the work. WhatsApp the VIN, year and fault description — we reply within working hours.