A Very common question from the informed BMW owner is, "What BMW ULF module do you ship with your Bluetooth kit?*  This is actually the best question that you could ask a vendor of any BMW control modules including your local BMW dealer.  The answer from us is the newest one that we can find worldwide, which is the The latest version available worldwide from BMW   The reason is as follows:

The BMW Bluetooth Control module (ULF) also known as "BMW Universal Hands-Free System with Bluetooth® Wireless Technology" was manufactured by Visteon (the Ford Automotive electronics spin off).  Visteon provided BMW a custom version of their MACH Voice Link starting in 2002.  The Voice-link system was designed to connect directly to the BMW Universal II phone wiring harness connector, that was put in all BMWs (except new Style) starting around March 2002.  Because of some initial challenges with the first generation Bluetooth module, Part number 84 21 6 934 552 was terminated in June 2003, while Visteon worked together with BMW to address some of the issues and release a new part number releases that contained updated hardware and software revisions.  It is easy to track the history of the ULF modules by examining the BMW Electronic Parts Catalog as shown below or the BMW Compatibility matrix.

Available part numbers of the Bluetooth ULF from BMW

84 21 6 934 552 end of life 06/03 1st generation
84 21 6 938 610 end of life 10/03 2nd generation
84 21 6 934 961 end of life 03/04 3rd generation
84 21 6 950 089 end of life 06/04 4th generation

84 21 6 945 387 end of life 01/05 5th generation

84 10 6 955 522 end of life 10/05 6th generation

84 10 6 969 268 end of life 04/06 7th generation

84 21 6 958 358 end of life 05/06 8th generation

84 10 6 987 546 end of life 9/06 9th generation

84 10 6 980 130 end of life 11/06 10th generation

84 10 9 133 329 end of life 01/07 11th generation

84 10 9 145 007 end of life 05/07 12th generation

84 10 9 154 358 current production 13th generation


It is interesting to note that you are unable to purchase any ULF module part numbers from a US dealer except the first generation 84 21 6 934 552.  I am told this is due to a BMW NA stockpile of these old parts and BMW AG's refusal to use the old technology in the new cars.  With so many units in stock, they have got to get rid of them somehow.  If you purchase a new BMW with the BMW Bluetooth / Voice recognition module (not Assist) it is likely that you will get either the 6th generation module or newer (The newer parts used in production BMWs do not seem to be available for purchase anywhere except as used parts)

The difference between the First Generation and Later Generations appears to be a pretty closely guarded secret as to not discourage BMW owners from purchasing the old system, and getting them out of BMW's warehouse.

The information gathered below comes from numerous conversations with engineers on the project and others in the know.......

BMW Part number 84 21 6 934 552-02 First Generation ULF module - Offered by other Vendors

BMW Bluetooth E38 E39 E46 X5 Navigation Sirius Hands-free  BMW Bluetooth E38 E39 E46 X5 Navigation Sirius Hands-free  BMW Bluetooth E38 E39 E46 X5 Navigation Sirius Hands-free

The first generation BMW ULF module is referred to as the first generation ULF module as it was the first Bluetooth ULF module to be installed in BMWs and was the first to have built in Voice recognition. 

This first generation version of the ULF module is equipped with an old generation Digital Signal Processor (DSP).  The DSP was upgraded starting with the 84 21 6 950 089 ULF module in order to drastically improve the voice quality in both the speaker and microphone of the system.

This first generation version of the ULF module is equipped with Older Hardware and Older Software HW. Rev.: 06 and SW Rev.:38.  The major differences in the Hardware between the first generation and newer 5 Generation and higher are specific to the lack of Bluetooth antenna optimization at 2.44 GHZ (the Connection to your Cellular phone), AND lack of support for the new DSP to improve hands-free voice quality.   From a hardware perspective you can see some of the component changes shown in the images above and below.  The major differences in the Software between the first generation and the newer 5 Generation and higher are lack of support for additional features such as viewing of SMS on your BMW display, and lack of support for additional Bluetooth phones and Bluetooth phonebook transfer features.   From a software perspective another way to tell is to conduct a side by side comparison of the two module, which I am happy to do for anyone willing to stop by.  For example, my Sony Ericsson phone does NOT transfer the phonebook to my BMW using the 552 ULF module although transfers the phonebook flawlessly to the 84 21 6 945 387 Or higher part.  In my personal usage experiences, the audio quality of the first generation is not as clean with some static even during the voice recognition.  This alone is the biggest reason why I started investigating getting the newer generation ULF modules even though they were so difficult to get.

From a Bluetooth Antenna optimization and connection standpoint the first - fourth generation ULF modules carried an older FCC registration NT8 - 14b4093KAFSWMStarting with the 84 21 6 950 089 ULF Module a VERY significant hardware change was made to improve the Bluetooth connection between the module and the Cellular phone.  Details of this change are shown in the following FCC documentation.  Notice the description of this change; "in order to stabilize and optimize the radio frequency generation" indicating the first generation thru third generation ULF module's Bluetooth connection are unstable and NOT optimized for performance.  The reference "to only change applied" is specific to the changes from the 84 21 6 934 961 to 84 21 6 950 089 ULF module.  This hardware change carried forward in the new ULF modules, and can be easily detected in the hands-free audio quality when comparing the modules side by side.

Overall the major differences are audio quality, Bluetooth connection performance, and support for additional features such as SMS and additional Bluetooth phones.

BMW Part number 84 10 9 154 358 13th Generation ULF module - Available from Bimmernav.com

BMW Bluetooth E38 E39 E46 X5 Navigation Sirius Hands-free   BMW Bluetooth E38 E39 E46 X5 Navigation Sirius Hands-free   BMW Bluetooth E38 E39 E46 X5 Navigation Sirius Hands-free

The new 13th generation ULF module started production in May 2007! with significant hardware and software changes for optimizing the hand-free audio quality, speeding up the connectivity between Bluetooth devices and support for additional Bluetooth phones.  This ULF module has been widely used in many BMW retrofits although is not available for purchase from US BMW dealers.  Purchases only can be made in large quantity international shipments such as BMW Germany.  The 13th Generation ULF modules are Software revision number 90, and hardware revision number 13.  In other words there have been 13 significant hardware improvements since the launch of the Bluetooth module from BMW, and 90 significant software revisions and bug fixes.  Anyone can see in the above pictures the obvious hardware changes in the images above.  The software changes are noticeable in the operation of the unit.

Starting with the 84 21 6 950 089 fourth generation ULF module the hardware was changed significantly and the FCC required a new FCC ID:FCC registration NT8 - 14B4093KAFSW2

From a software standpoint, the software algorithm in the DSP was changed in the newer ULF modules offering another significant voice quality improvement over the earlier version ULF modules.  This change was the most significant, although other software changes include changes to the Bluetooth OBEX profile allowing the transfer of phonebooks from more Bluetooth phones to the BMW's displays.

We have found the 84 10 9 154 358 ULF module to be a significantly better performing ULF module than the previous generations and would recommend this version to anyone considering Bluetooth.

The 13th generation ULF modules, supports a large phonebook capacity of 1,000 names in the address book vrs only 500 names in the previous generation ULF modules.  A noticeable difference can be found when pairing new devices or entering the vehicle as the 13th generation ULF pairs to your phone quicker   

*NOTE: Our Bluetooth Kits come with the latest Generation BMW ULF modules Available as shown in the BMW Compatibility matrix(and NOT the problematic first generation 84 21 954 552 others are selling,   Be careful on getting older ULF modules as some people have had difficulties and incompatibilities with the old first generation ULF modules.  Why use Our Bluetooth Solution?  We advise to stay away from any BMW part number 84 21 954 552 1st generation ULF module, and stick with the more recent versions. 

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