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Posted: Tue 26 Mar, 2019 10:52
by Southernboy
I recently did an EWS upgrade on an M52TU. The problem was that every so often, the car would crank but not start. After some extensive research I found that the EWS unit fitted to the M52TU / E36's and E46's had a sort of glitch in the program which resulted in error code 209 and the above mentioned issue.
This is easily cleared using a tool like INPA, but as I have experienced twice, the cost of a tow and having the code cleared is hugely expensive. The cure is to replace the OEM SW05 EWS module with the EWS3D SW06 module ( or newer version).
BMW Dealer wanted some stupid money for the new updated module, plus I would have needed to book the car in for programming etc and that was more very stupid money.
I found a guru in Prague who has his own business doing BMW electronics programming and repairs. He asked me to download the BIN file from my OEM EWS and email it to him in Prague. To do this one needs specialised tools which I don't have, so I found a local fella in Johannesburg who did it for me - free.
I emailed the file to Prague and the guru there had a new SW06 EWS module which he then downloaded all my car's info onto and posted to me here.
He provided me the install instructions which were super simple, but again required a special tool to then sync the new EWS to my DME. Again a local fella did this for me - free. took about 3 minutes..

Subsequent to that the fella in Prague, found my post on .org regarding the problem and has sent me some valuable information regarding the workings of the EWS / DME / Key scenario, and this is what I am posting below. Anyone who has any electronics issues can PM me and I will provide him/her with the contact info to this man. Bear in mind he does this for a living, so he charges a fee for his work.
His charges for helping me out were worth lots to me compared to the costs of going to BMW. Around £50 vs £200.

Hi Barry,
I found your thread on zroadster website, and I can see that there was quite a lot of information from other guys, some of these were some nonsense. If you need some more detailed info on what was going on, I can be of a help or provide you with some further information.

At first, for example, you were advised that the crank-no start situation can be caused by over-starting. Basically, this information is sort of correct, BUT it is not a protection for overstarting, but it only is a correlation. When multiple long start attempts are performed, the starter puts a strong current draw. This means, the on-board voltage during the starting attempts drops. As the rolling code needs to be matched between the EWS and DME and this is done via communication between these units, the voltage drop can cause that the data is sent on one side but not received on the other side (or not received correctly). After some starting attempts it can cause the ISN (rolling part) to be impaired and needs to be reset. In your case it was probably not the culprit as you had the problematic SW05 version of EWS3D, but this also can happen.

Attached please see the oscilloscope measurement on the EWS-DME signal line to compare the signal which is not OK (can be caused by voltage drop, EWS failure or EWS-DME wire damage). The other image shows the correct square-shaped signal.

Another thing is reading the key data by DIS - this is not possible. The DIS has only an ability to: sync the EWS-DME ISN and block the lost keys so that these won't work with the car anymore. Any attempt to change this data requires a working key inserted in the ignition switch, and this one can not be blocked by DIS. Some tools when improperly used can block also the key which is in the ignition, for example BMW Scanner 1.4 is able to do it (seen it).

The only official way to obtain new keys, EWS or ECU is from the dealership. In some cases with E31, E36, E38, E39 made in period (January 1995 to November 1997) even the factory has a problem with making the proper key because the data stored in the factory's database is incorrect as per TIS 00512101/0198.

The keys are stored as two codes according to VIN:
• HA code which tells the factory how to cut the key via CNC machine
• Transponder coding containing data about VIN etc. and then key number (1-10), solid part of the key number.
After ordering the key depending on the key blank, the factory cuts a new key and programs it to fit the EWS and locks with which the car left the factory. AFAIK there are several plants over the world able to cut and program the key and the factory orders them at the one closest to the customer. This information can be found in TIS.

The EWS contains ISN and keys data, I am not sure if it contains the VIN from the factory, and it definitely does not contain the central coding key. After getting the new EWS, it needs to get coded (transfer the central coding key from another unit storing it - varies by the car model) and synchronized to the DME.

The DME ordered from the factory is ordered as BASIC DME (or DDE in case of diesel) and comes unprogrammed. Does not contain VIN, ISN, maps, anything. After fitment in the car it needs to be programmed by the proper software (this can be found in the ETK as "programmed control unit" and in ISTA/P or GT1 you need to input the software number, mileage, VIN etc. After programming, the EWS gets married to the DME and using no diagnostic tool can be re-married to another EWS. Also the adaptations are reset during this process.

The only way to re-use the pre-used DME or DDE with another car (EWS) is:
• in case of EWS2 or EWS3/EWS4.3 in EWS2 mode - eg. E38/39 with M52 (not TU models), TDS and similar you can read the ISN from the DME with INPA and write it to the EWS also with INPA.
• In case of EWS3 you need to either read a full bin from the DME, find the ISN and write it to the EWS dump using AK90, xProg or similar, then sync. Or read a full bin from the DME/DDE, virginize it (meaning in a simplified way to change the ISN value to all FFs), then marry it to the EWS using diagnostic tool like if it is a new DME/DDE.
I also have read an opinion that EWS is a simple relay. This also is only partially correct. This was correct with the EWS1 system, which was fitted only in 1994. From January 1995 and on there is EWS2 and in some models since 3/1997, on other models since 9/1998 there was EWS3. Only E36 body cars fitted with engines coming from E46 (simplified explanation, basically M52TU, M54, S54) are fitted with EWS3D, which has the same connector like EWS2, but with a different pinout (does not have a separate Transmitter/Receiver module as all is included in EWS3D module like in normal EWS3 unit) and has a regular k-line (EWS3D has only K-bus for which the E36 chassis does not have a gateway). This way BMW was able to put all the EWS3 functionality in E36 chassis with an ability to be diagnosed and EWS synced with DME.

Feel free to share this information on the forum :-)

If there are any other questions, let me know and when I have some time, I will answer.


Posted: Tue 26 Mar, 2019 13:03
by Gazza
Great info, thanks :D


Posted: Tue 26 Mar, 2019 13:20
by Southernboy
I figured you would appreciate it... :wink: