In short
Cloning an engine ECU means copying the contents of yours, which is faulty, to another compatible unit: the software, the calibration and the immobiliser and vehicle data. That way the replacement ECU behaves exactly like the original and the car starts with its own keys, without having it programmed at the dealer. The replacement unit must have the same hardware part numbers and the memory of the original must still be readable. Engine ECU cloning starts from from €100 + VAT (€121 including VAT). We do it at our workshop in Alcalá de Henares or we come to you within the Community of Madrid.
Your ECU has failed: the three ways out
The engine ECU (engine control unit) is the computer that manages injection, turbo and ignition. When it fails completely, the car will not start, or it starts and cuts out. You have three options:
| Option | What is done | When it fits | What to bear in mind |
|---|---|---|---|
| Cloning | All the contents of your ECU are copied to another unit with the same part numbers | The original is faulty, but its memory can still be read | You need a compatible unit (new or used) |
| Programming a new one at the dealer | A new ECU is fitted and the manufacturer programmes it and pairs it with the car | The original memory is lost or cannot be read | Usually requires a new unit and, depending on the make, all the car's keys |
| Repairing the original | The damaged component inside the ECU is found and replaced | Fault confined to one component and memory intact | Not always possible; depends on the fault and the model |
The two we do are repairing your ECU internally and cloning it. In many cases cloning is the option that keeps the car off the road for the shortest time and avoids relying on a new unit. We will tell you which one makes sense once we have seen yours.
When an ECU is cloned
- Water: leaks through the bottom of the windscreen, through the engine bay or after driving through a flooded area. Moisture corrodes the circuit little by little.
- Voltage spikes: jump-starts with badly connected leads, welding on the bodywork without disconnecting the battery, an alternator that overcharges.
- Knocks and vibration: an accident or a broken bracket that leaves the ECU moving about.
- Internal failure with no clear external cause, which also happens with age.
Before writing off an ECU, it is worth ruling out fuses, relays, earths and wiring, which produce the same symptoms. If you are not sure, we start with electronic diagnostics. And if the problem is that the car will not start but the ECU is fine, what you need may be a no-start solution.
What gets copied and why the car starts again
Inside the ECU there are several memories, and each one stores part of your car's identity:
What passes from one ECU to the other
- Software and calibration
- The program and the maps your engine runs on
- Immobiliser
- The data that lets it recognise your keys or the module that validates them
- Vehicle data
- Chassis number (VIN) and equipment coding
- Adaptations
- Learnt values for components such as injectors or the throttle body
A new ECU, or one from another car, does not have that data, or has another vehicle's. That is why, even if it fits the connector, the immobiliser will not let it start. When cloning, the replacement unit ends up with exactly the same contents as yours.
How to choose the replacement unit
We can source the replacement unit or you can supply it. If you are looking for one yourself, the key is the label. Before buying anything, compare:
- ECU manufacturer and model (shown on the label).
- Hardware part number: it has to be the same. That is what guarantees the circuit and the memories are identical.
- Car manufacturer's part number: if it matches, so much the better; if only the software differs, it is normally resolved when cloning.
Send us a photo of both labels before you buy and we will confirm whether it will do. The wrong unit is money down the drain.
When it cannot be cloned
- The memory of the original is damaged or unreadable: there is no data to copy.
- There is no compatible unit with the same hardware part numbers.
- Some recent ECUs have protections that prevent them from being read or written with the usual methods. With the make, model, engine and year we can tell you whether yours is one of them.
In those cases we explain what alternative is left, even if it does not involve us.
How we do it
Preliminary check
we confirm that the fault lies with the ECU and not with its power supply or wiring.
Checking the replacement unit
we compare part numbers before touching anything.
Reading the original
depending on the model, through the connector or by opening the ECU to read the memories directly. We keep the copy.
Writing to the replacement
we copy the software, calibration, immobiliser and vehicle data.
Fitting and testing
we start the engine, clear the fault codes in all the control units and check that the engine is running normally.
How much it costs
Engine ECU cloning starts from from €100 + VAT (€121 including VAT). What makes the price vary:
- How your ECU is read: through the connector or by opening it.
- Whether anything needs repairing or preparing in the original so that it can be read.
- Whether we come to the car, which is the usual case when it will not start. We explain it in mobile service.
You have all the published prices in prices.
Send us a photo of the label on your ECU and, if you already have it, of the replacement one. We will confirm whether it is compatible and the price.
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