If you own a modern BMW and have been interested in tuning it, you will no doubt have come across lots of information regarding tuning and unlocking the ECU’s on these cars.

There is lots of information, misinformation and confusion around ECU unlocking on these cars, even amongst tuners, so we have made this simple guide to help simplify the key facts.

The first thing to establish is the manufacture date of your ECU. This is not the same as the build date of your car, and certainly not the same as the registration date of your car.

In order to determine this, if your car's build date (stamped in several places around the car) is prior to June 2020, you know for sure that you couldn't have a pre June 2020 ECU.

Similarly if your registration date is prior to (in our experience) around September 2020 (in the UK at least), then its very unlikely you have a post-June 2020 ECU. Without wanting to state the obvious, this is because between the car being manufactured and it being registered, it has to be shipped, delivered to the dealer and then registered, which typically takes a couple of months.

If your build/registration date is later than this, late 2020 or early 2021 then its a mixed bag. You can either check yourself by looking at the ECU label, or visit a tuner. Pay us a visit and we will happily check your ECU free of charge.

If your car is late 2021 build onwards, then its less and less likely  that it will feasibly have a pre June 2020 ECU.

If your BMW’s ECU is manufactured prior to June 2020, then the process is quite straightforward. Prior to tuning the ECU you may still require a Bench unlock, but this is a (comparatively) straight forward step. If your ECU is manufactured after June 2020, you will require a FEMTO unlock or to consider alternatives to flashing the ECU (covered later).

How to read your ECU date:

The manufacture date is written on every ECU but is in an unusual format and is in very small text.

With the ECU removed from the vehicle, look for the label opposite. In this example the date is written "20-07-28" this is formatted YY-MM-DD (Year, Month and Day). In this example the ECU was produced on 28th July 2020. This is post June 2020, so would require a Femto Unlock.

femto_ecu_date
femto_ecu

What is a Bench unlock?

All this means is that any competent tuning company will need to connect an appropriate tool directly to the pins of your ECU and perform an unlock procedure. This is reasonably straightforward and fast to do on most ECU’s, and can be done in house as part of the remapping process. Ultimately requiring a bench unlock is not a big deal, and for most engines doesn’t add significant time to the process.

The main exception to this would be the S55 engine, purely due to the location of the ECU. Its still an easy job, but as the inlet manifold needs to be removed it’s a little more involved.

benchunlock
femto1
femto2
X4mbadge

What is a FEMTO unlock?

The ECU must be removed from the car and physically posted to FEMTO in Finland in order to be unlocked. The procedure cannot be performed remotely. You can either approach a tuning company to do the whole process (we can do this for you) or you can send the ECU to FEMTO yourself.

Doing this yourself is not especially difficult, you simply need to:

  • Park the car somewhere where it will not need to be moved (it will not run without an ECU).
  • Register an account at https://orders.femtoevo.com/
  • Purchase the appropriate service for your ECU. Choose BM3, MHD or the OBD tool depending upon your and/or your tuner’s choice of platform. Please discuss this with your tuner prior to ordering.
  • Ship your ECU via a secure, insured courier service to the address they give you.

At the time of writing, just as an example an unlock for an S58 costs €750EUR. This fee is purely for the unlock and does not include tuning the ECU, or a secure courier to and from Finland.

Be aware that depending upon where you live, the returning parcel (despite being your own property) may well attract customs charges. In the UK you shouldn’t be charged duty on the return of your own goods but in our experience, it is very likely that you will be, and all the time that you argue it, your car is undrivable. In any case, marking the parcel as “Temporary Export” and “Return Goods Relief Claimed” should help.

Our advice at this point is to:

  • Disable Over the air updates in your car. This prevents ECU updates being done remotely.
  • Never take the car back to a Franchised BMW dealer. If the dealer updates your ECU then it will be wiped, re-locked and you will be back to square one. Yes you can ask them not to, but there are countless cases of them forgetting, misunderstanding or otherwise.
    As such our advice is to find a good independent specialist workshop for servicing going forward.

 What Alternatives are there?

If you would prefer not to go down the FEMTO unlock route, there are fortunately some alternatives. We manufacture a range of excellent plug-in tuning modules that get excellent results without requiring an ECU unlock.

Our unit for the S58 for example costs only £299.99 delivered in the UK. It gets very similar results to a stage 1 tune, is still completely configurable and can be custom tuned on the dyno but can also be installed at home.

These units can be transferred between vehicles, and have the option of Bluetooth control to allow the maps to be chosen or the tune to be disabled from the drivers seat. The Bluetooth option also allows for remote reprogramming and datalogging.

The other big advantage vs flashing the ECU is that the unit can be tracelessly removed. This means that if for example trading the car in, so long as the unit is removed, there are no issues.

You can search for your car using the vehicle selector at the top of this page, or visit our BMW Tuning page.

Examples and Testimonials

This dyno test video of our unit fitted to a 330e is a great example of the performance gains possible with one of our tuning boxes.

The examples above for the S58 and B58s are a good illustration of our unit performance. 

More information on how the tuning box works on the B48 can be found here: B48 Tuning