Live Tuning Sessions

Your tuner watching your engine, and adjusting it, while you drive

In a live session your tuner sees your engine's data as it happens and can change your tune while the engine is running. You are at the car; they are wherever they are. It is the part of tuning that cannot be done by sending files back and forth, because it needs somebody watching the numbers move and changing something in response.

It is not remote control of your computer. Your tuner cannot see your screen, open your files, or do anything to your machine. What they can do is read the channels your ECU is already reporting, and send changes to your tune — the same changes you could make yourself on the ECU Settings and VE table pages.

What you need

A live session key. This is bought separately from a tune — holding a tune licence is not enough. Enter it on the home page under Tune licence.
Your ECU plugged in over USB, and the engine able to run.
An internet connection at the car. A phone hotspot is fine.
Somewhere you can safely run the engine, and — normally — a phone call open with your tuner, so you can talk while they work.

Telling your tuner you are ready

Agree a time with your tuner first — this is not a booking, and they will not always be at their desk. When that time comes, be at the car with the engine able to run, find the Live tuning card on the home page and press Tell my tuner I'm ready. There is a box beside it for a note — anything they should know before they join:

"Boost drops off above 5000rpm" · "Idle hunts when cold"

That note is the most useful thing on the card, because it is what your tuner sees beside your name when they pick who to work with next.

The card then says Waiting for your tuner. Leave the app open. When they answer, the card changes by itself to show the session with a Join button — you do not need to refresh anything or watch for an email.

You never have to look up any numbers. Your tuner is told which car you are asking about automatically, from the ECU on your cable and the licence you entered. There is no ECU identifier to read off a screen and nothing to type.

If you change your mind, press Cancel. A message you leave alone expires by itself after two hours, so one you forget about will not sit there indefinitely — which is also why it is worth telling them at the time you agreed rather than the night before.

When the session starts

You do not have to do anything. When your tuner answers, the session starts by itself — you asked for it, and asking is the only decision there is to make. GTune tells you it has begun and who is on the other end.

A banner then sits across the top of the window for as long as the session lasts. It names your tuner, says what they are allowed to do and for how long, and counts what they have changed. Each change is also announced as it happens, so you can see what they are doing at the time they do it — not only afterwards.

End session is on that banner throughout, and it is yours alone. Your tuner cannot stop you using it and does not have to agree to it.

The session records. A live session always writes a log of everything your ECU reported, on your machine. That file is the real record — better than anything the network carried — and it is sent to your tuner afterwards so they can go over the drive properly. If nothing is being recorded, the session will not start.

What your tuner can and cannot do

The banner says what this session allows, and the app enforces it — a session cannot do more than it was issued for, whatever anybody asks. Typically:

Read every channel your ECU reports, at 10 times a second.
Change tune values — VE cells, ignition, boost, settings — temporarily. Temporary changes are lost when you switch the ignition off, which is the safety net: if anything is wrong at the end of a session, turning the key off and on again puts your ECU back to what it had.
Store changes permanently, but only if the session allowed it, and this is the one thing worth understanding — see below.

What no live session can ever do, whatever it says:

Update your ECU's firmware. A bad tune value is undone by writing another one; a bad firmware write leaves you with a dead ECU, and that is not something this will do over the internet at all.
Read your files, your other maps, or anything else on your computer.
Continue after you end it.

Temporary versus permanent

Almost everything a live session does is temporary. Your ECU holds the new values while it is running and forgets them at the next key cycle. That is deliberate: it means the worst outcome of a session that goes wrong is that you turn the ignition off.

Making changes permanent is a separate act, and the session has to have been issued with permission for it — the banner says so from the start if it was. When it happens you are told, as you are told about every other change. If you are unsure at the end of a session whether you want to keep what was done, you do not have to decide there and then — a session that is never made permanent simply leaves your ECU as it was.

If the connection drops

Nothing is lost. Your recording keeps running on your own machine regardless of what the internet is doing, and any data your tuner missed is filled in automatically when the link comes back. If the drop is at the car — a cable knocked out — your ECU has a couple of minutes to come back before anything is torn down.

If your tuner's end disappears, the session holds briefly for them to return and then ends by itself.

Afterwards

The recording from the session is sent to your tuner automatically, in the background, when you have a connection. You do not have to do anything with it, and it does not matter if you drive off straight away — it goes when it can. You will find it listed on the home page under recordings either way.

One key, one car. A live session key covers the car it is first used on, the same way a tune licence does. If you have two cars you need a key for each — and if your tuner cannot see you when you tell them you are ready, the usual cause is that the key is registered to your other one.