Siemens MS43 - Outright Sale

ECU Fits Years: 2000 - 2003

Warranty: 5 Years

Product Code:

Availability:In stock

$699.00 699.00



For this service we will send you a Rebuilt ECU that needs to be adapted or "Synchronized" to the EWS module of your car.

NOTE : You will need a BMW scanner that has the capability of performing the ECU to EWS Synchronization in order to make this ECU work in your car.

The ECU will be programmed to your Specific vehicle model, year and transmission type.

The ECU will be in a VIRGIN estate, meaning that needs to be synchronized to the EWS before attempting to start the vehicle.

WARRANTY: 5 years



ECU/ DME Location


Symptoms of a Bad MS43 ECU:

  • Outside Cold temperature affects car starting
  • Cleaning of Dust, debris or Corrosion
  • DME Self Diagnostic : RAM Check failed Error
  • Engine Stalls
  • Engine Cranks but doesn't start
  • EML light come On
  • RPM speed limiting Error
  • Various misfires and Oxygen sensor codes
  • Electric fans not working


How to install the ECU

GT1 Scanner -DME to EWS Alignment Instructions

Launch-X431 - DME to EWS Synch Instructions

General Technical ECU Troubleshooting Guide


My Mechanic/ Dealership says that you can't Re-Program, Re-code or swap a used BMW ECU between cars. How can you help me?

We have reverse engineered these ECU’s and developed proprietary software along with equipment that allows us to Reprogram used Ecu’s to your car’s VIN Number and EWS Immobilizer system.


Why can't I buy a used BMW ECU and installed myself?

Because if you install a used ECU in a BMW starting from years 1995 and on, the VIN number and most important the Immobilizer Codes will not match. The non matching Immobilizer codes and different VIN number will not allow the car to Start. With a used ECU’s from a different car, the starter motor might work but as the immobilizer codes stored inside the ECU does not match the ones on your EWS security module there will be no OK signal for the ECU to start the engine.


What is the Immobilizer codes or commonly called "Rolling Code"?

BMW’s have immobilizers modules called “EWS” which is a anti theft device feature unique to the BMW brand. The way the EWS works is by a code or  “Rolling code” that changes every time the car is turned off. This unique safety feature makes it virtually impossible to swap used ECU’s between BMW cars as the used ECU’s will never match the EWS from your car.

Newer generation BMW’s carry the CAS module and smart key function, a newer version of the EWS system. More advanced than the previous EWS the principle of operation is basically the same were as you cannot install a used ECU from a different vehicle in your car.



An “EWS OFF” ECU will have the security system feature deleted internally, that means that the ECU can be installed in a car without the need to Synchronize - Align the ECU to the EWS.
Removing the EWS from the car simplifys the starting and running of the ECU and Engine.
However NOT ALL BMW ECU’s can have these feature removed.


So how we can offer Repairs and Outright ECU’s for BMW ?

We have reverse engineered ECUs and developed many proprietary tools thru the years that allow us to perform programming operations even the dealership can’t.
We can erase old coding along with programming of VIN numbers that are not possible even with the most advanced and expensive scanner tools.


When I purchase an Outright Sale rebuilt ECU, will the unit be Plug and Play?

“NO”. Our Outright Rebuilt ECU’s will be programmed to your BMW’s VIN number and correct software that matches your vehicle. However, due to the fact the EWS system have a random “Rolling Code” we can’t guess what this random code is. Therefore, we RESET this feature to make the ECU able to be paired with your car’s EWS.

In order for the Outright Rebuilt ECU to work in your car, an ECU to EWS alignment - Synchronization has to be carried out. This operation is done using a BMW scanner that contains the feature of alignment - synchronization on its software “Note that not all BMW scanners can carry out this operation”. Here is a short list of most used scanner can carry out this procedure | GT1, Autologic, ISTA, INPA and others. The alignment - synchronization procedure takes less than 5 minutes to “MARRY” the Rebuilt Outright ECU to your cars EWS, once that is done the ECU will be ready to start the engine.


If you Repair my ECU, do you I need to “re-flash”, "re-code" or “re-program” the ECU before installing back into my car?

NO. ECU reprogramming is not required because we will always make sure latest versions of software along with correct ECU to EWS matching is done in our laboratory.
Once we repair your unit, it will be 100% plug and play, already tested in one of our actual Tester vehicles.

Siemens MS43 - Outright Sale