What the TCU controls
Shift points, shift speed, clutch or line pressures, torque-converter lock-up, kickdown, launch behaviour, adaptation values and the maximum torque the gearbox will accept from the engine.
Gearbox types
Dual-clutch (DSG, S tronic, DCT)
Two clutches, one for odd and one for even gears, with the next gear pre-selected. Clutch pressure and torque limits are key calibration areas.
Torque-converter automatic
A fluid coupling and planetary gearsets. Shift logic, pressures and lock-up behaviour are key areas.
Why it is often linked to engine remaps
If an engine calibration raises torque above the gearbox's software limit, the TCU may intervene — reducing torque or slipping clutches. Some gearboxes therefore need a TCU calibration to suit an engine remap; others do not.
Condition comes first
Software will not fix worn clutches, failing solenoids, low or degraded fluid, or mechanical damage. Slipping, flare, judder, harsh shifts or warning lights need diagnosis. Fluid service history is important.
Using this guide
This guide is general and educational. Vehicles differ in their engines, control units, software and emissions equipment, and manufacturers' handbooks sometimes give specific instructions that take priority over general advice. If anything here conflicts with your handbook or a warning on your dashboard, follow the handbook and get the vehicle checked.
We do not use customer stories or invented figures in our guides. Where something depends on the individual vehicle, we say so.
How we approach a gearbox remap
We start with suitability rather than a sales pitch. Before any calibration is written to a control unit we want to know the vehicle is healthy: existing fault codes, boost or fuelling problems, a slipping clutch, a worn gearbox or a blocked DPF all need to be dealt with first, because tuning is not a substitute for repair and can make an existing weakness more obvious.
Where the vehicle is supported we explain what the proposed calibration is intended to change, what checks are needed and what the agreed scope of work includes. We do not publish universal power, torque or fuel-economy figures, because results depend on the individual vehicle, its condition, its software and how it is driven. If a remap is not the right answer for your vehicle, we will tell you.
What to send us before booking a gearbox remap
The quickest way to get useful advice is to send the registration and a short description by WhatsApp or through the quote form. Support and suitability vary by engine, gearbox, control unit and software version, so a registration lets us check the right information instead of guessing. Any estimate given remotely is provisional until the vehicle has been seen and the required checks are complete.
- 01Vehicle registration and approximate mileage
- 02Make, model and engine size, if known
- 03Any warning lights, messages, symptoms or fault codes
- 04Existing remaps, tuning boxes or hardware modifications
- 05How the vehicle is used — commuting, towing, short trips or heavy loads
- 06Whether the vehicle is currently in limp mode or will not start
Visiting the workshop for a gearbox remap
All work is carried out at our single workshop at Unit 2, Lancaster Works, Kingsbridge Road, Manchester M9 5SP. We do not run a mobile remapping service and we have no other branches, so every a gearbox remap enquiry is booked into the same Manchester workshop. Visits are by arrangement: please call or WhatsApp before travelling so we can confirm the vehicle, the time and what the visit will involve.
Access is through the black gate. Call when you arrive so we can let you in, then keep left towards the rear of the site. We are open Monday to Friday 8am–6pm and Saturday 8am–1pm, and closed on Sunday. If the vehicle is in limp mode, showing a serious warning or will not start, tell us before setting off so we can talk about whether it is sensible to drive it or whether transport should be arranged.