Factory Bluetooth Retrofit

Tools Required

• Basic hand tools
• NavCoder software (optional)

Facilities Needed

• None
  

Parts Required

• (1) BMW Bluetooth TCU: p/n varies, price (used): $100 - $150.
• (1) DB25 to 54-pin Adaptor Harness: p/n 84 12 0 308 375, price: $37 (list).
• (1) BMW Bluetooth Antenna: p/n 84 50 6 928 461, price: $26 (list).
• (1) FAKRA Cable: 4' minimum length, price: $6-$12 (on eBay).

Getting Started

Replacing the useless stock phone system in your BMW with a factory, hands-free "Bluetooth" system is a fantastic way to modernize your car, gain practical benefits and fully utilize your onboard electronics.

Aftermarket BT devices (such as Grom and MediaBridge) require your radio to be continuously on and in CD mode in order to function. But a factory BT system operates independently, in the background and always at the ready. In addition, the CD changer line remains open (for use as an MP3 music source or aux-in, for example). So, you can finally use all your car's electronics including the built-in microphone (in the headliner) and steering wheel controls, plus view extensive phone information on your nav screen or MID display. What could be better?!

There are two different ways to achieve this:

1. ULF (Universal Phone Unit): Compatible with most BMW's regardless of installed electronics and model year; Requires phone pairing button; Accepts phone-specific cradles (in center of armrest) which charge your phone while boosting its signal thru the roof antenna; However, ULF's are expensive and hard to find; Requires more installed parts.
2. TCU (Telephone Control Unit): Partially compatible with E38's thru 08/00 but fully compatible after that; No pairing button needed (pair within two minutes of starting your car); Can't use cradles; Cheaper and more numerous than ULF's; Fewer installed parts required.

Considering cost, simplicity, and my car's model year, I chose to install a TCU. The good folks at BimmerNav are now offering a TCU kit, but it costs as much as their ULF kit: $800. As described here, a TCU retrofit can cost under $200.

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BMW made several different ULF's and TCU's over the years. Compatible TCU's were made starting in late 2004, with the most recent being p/n 84 10 9 195 455 (from 3/08 and still available from BMW). For a summary, see BMW TCU and ULF Part Numbers.

There are some limitations:

• Compatible ULF's and TCU's are made for voice communications, not music streaming. Only the latest TCU's offer streaming, but they're not compatible with the E38 7-series. One option is to use an aux-input in place of the CD changer, for phone-based music. (This method also avoids data loss from A2DP compression.) Another option is to install a Grom exclusively for wireless streaming. (The factory Bluetooth system mutes radio audio during a call, and should thereby take "priority" over the Grom.)
  
  
• Navigation voice control will be lost for E38's built before 08/00, unless an SES voice module is installed. If this is a deal-breaker, get a ULF instead. See step 8 below for more. From 08/00, voice control can be shared with navigation after simple coding with NavCoder software. See my NavCoder section for instructions.
  


• If your BMW is not equipped with DSP sound, you will probably need a supplemental amplifier if you cannot obtain suitable volume from your phone.

While there is much variation in BMW models, the information here may be applicable to several BMW models from the late '90's-on.

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TCU Specifics

Used TCU's are commonly available on eBay. Beware some sellers claim "Bluetooth" when in fact the TCU is an older, non-BT unit. Confirm Bluetooth by the label:

Look for the Bluetooth logo (left center) and "PK" (Pass Key) code. This code is required to pair your phone. If this label is missing or illegible, do NOT buy it! The two peel-off labels will most likely be missing. This is OK.

Verify "BMW....IBUS", as only i-bus units are compatible with the E38 7-series. The production date (above: January 13, 2007) will relate to the software and hardware version ("SW" and "HW", respectively). Look for late production dates to obtain the newest technology.

FAKRA Cable

The BMW cable which connects the BT antenna to the TCU (p/n 61 12 0 137 616) is a FAKRA-type cable and was discontinued on 6/3/16. Not to worry. This is a generic part and may also be purchased on eBay. You will need a female-female connection with 4' minimum length, in size RG174.

The drawback of a generic cable is that its connector may -- may -- not fit the keyed ends of the TCU and BT antenna. If this happens, the keys must be removed by filing them away. But do NOT remove the retainer tab. See image below:

Mounting the BT Antenna

The perfect location for the BT antenna is inside the left (driver-side) C-pillar, just below the passenger courtesy light. Running the FAKRA cable thru the trunk wiring pass-thru is surprisingly easy compared to some cars.

Unfortunately, removing trim pieces for access will result in broken fasteners. The question is how many. Follow my instructions to minimize the damage.

Mounting the TCU

Unlike the ULF, a factory trunk mounting bracket is unavailable for a Bluetooth TCU in an E38 7-series. For those interested in a clean install (like me), a random tie-wrap solution is unacceptable. An adaptor board can be made from plywood, and mounted on the video bracket.

Note the Bluetooth TCU is a large device. It's too big to fit in place of the old TCU. If mounted as suggested, it must sit as low as possible on the bracket. Even so, the TCU still contacts the taillight access door. Leaving this door ajar isn't an issue, since it's not visible after closing the larger nav access door. See Procedure sidebar below.

Procedure

Trim Removal

1) Start by removing the nav computer (if applicable). Allow computer's red light to extinguish BEFORE proceeding. Insert radio removal tools (or coat hangars) into slots to release retainers. Then, grasp black nav trim and pull firmly:

Once free, disconnect the two plugs and antenna wire. Set aside. Then, remove the black plastic trim surrounding the bracket's opening.

2) Release the two black plastic trim screws just right of both the nav and CD changer. Then, release the 1/4 turn fastener securing the taillight access door (left of nav opening). Now, remove left rear side trim by pulling out and up.

3) Pull out upper rivet on forward trim. Then, pull trim down to gain access to trunk wiring pass-thru (images above).

4) Moving on to C-pillar trim, lever out -- from the top -- the left passenger courtesy light and unplug. (Levering from the front will break the light's retainer clips. Ask me how I know.)

5) Release the three (3) now-visible trim retaining screws using an 8mm nut driver. See image below. Remove trim carefully by pulling out and up, in rocking motion. Afterwards, the trim will likely suffer from indentations in the (deteriorating) foam, left behind after handling. This is unavoidable. (It may be time to replace your headliner and pillar cover fabric.)

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Prep Work

6) Survey your installed equipment. Remove your old TCU and associated phone parts from both the trunk and center armrest (if any). Install blank center tray in armrest to replace any existing phone cradle.

Your old TCU is likely behind the brass-color video bracket. Remove the three 8mm screws to release bracket, as shown in image above left (red arrows). Unplug old TCU and discard. (Don't bother listing it on eBay. It's worthless.) Newer cars may have TCU mounted in front, directly on video bracket, as in image below.

For late-build models, note also the SES voice module in image above. This module will handle voice control of both Bluetooth TCU and navigation (after NavCoder programming of TCU). Cars without SES will lose voice control for navigation after Bluetooth TCU installation -- unless an SES module is installed. See note to step 8 below.

7) For cars build before 9/00 (which have no SES module), it will be necessary to jumper pins 11 and 14 in the black phone plug located in the armrest ("eject box"). This sends phone audio to the front speakers. See image below:

The pinouts on this black connector are very small and difficult to read. Use a magnifying glass for assistance.

8) Also for cars built prior to 9/00, verify the blue SES connector has a white jumper plug installed, as seen below:

NOTE: Installing an SES voice module in a car that did not come with one should enable voice control of both nav and notepad, along with phone, all without jumpering pins 11/14 in the armrest plug, as noted in this thread.

9) OPTIONAL (if necessary): Prepare new TCU and BT antenna for the FAKRA cable by filing off keyed metal ends of white coded connector of TCU and the black plastic keyed ends of BT antenna.

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Bluetooth TCU Installation

10) Plug adaptor harness into DB25 connection from old TCU. Return video bracket and secure with screws. (Your Bluetooth TCU will not fit back there.) Route 54-pin connector up through cut-out in bracket floor. See image below left:

11) Mount Bluetooth TCU and connect 54-pin adaptor. One mounting option is to tie-wrap it to the video bracket. A better solution is a plywood mounting board which attaches to the video bracket. See image above right and sidebar below.

12) Insert coat hanger wire (or similar) in trunk pass-thru grommet, up into C-pillar area. Tape FAKRA cable to the wire and pull it back through into trunk.

13) Route FAKRA cable safely behind trunk electronics and connect to white coded terminal of mounted TCU.

14) Connect other end of FAKRA cable to BT antenna. Then, mount antenna just above white AM/FM amplifier by utilizing the T25 screw holding black plastic protective trim inside C-pillar. See image below:

15) Done! Before replacing trim, test your installation: Temporarily re-connect nav computer (if applicable). Switch ignition key to accessory and attempt to pair your phone (within two minutes) using the Pass Key (PK) printed on your TCU label. Once successful, take optional final steps using NavCoder software as below:

• E38's thru 08/00 (without nav or SES module): Confirm voice recognition ("VR") is enabled (most TCU's come this way). Set emergency call number (if desired).
• E38's from 09/00 (with nav): Disable voice recognition (switch to SES). Set emergency call number (if desired).

16) Once satisfied, replace trim in reverse order. Finally note:

• BMW Bluetooth User Manual - for ULF installations, but mostly applicable.
• BMW Voice Control User Manual - make use of the separate voice-activated phonebook!
• Bluetooth Telephone Menus - my supplement for cars with navigation.
• Microphone, p/n 84 31 6 938 762 - new, noise canceling voice mic (optional).

Now place a Bluetooth call to celebrate!

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TIPS:

New Mic '762: I do not recommend this mic over stock simply because its noise-cancelling features cause audio cut-out upon low signal levels. This results in a completely silent "lost-signal" sound for the caller during conversational pauses, which leads to questions "...you still there?". To be heard better during a call, lean in towards the mic.

Audio/Volume: There are two different ways to control in-call volume: 1) phone, 2) system. System volume is only accessible by voice command, but not during a call. It has only three pre-sets: low, medium, high. System volume also sets the incoming call alert tone. A "high" tone can be quite startling when receiving a call. Furthermore, adjusting radio volume during a call has no affect. This leaves phone volume as the only effective volume control when in-call. To offset road noise, tighten the Speed Dependent Volume steps (SDV) when coding your TCU. See my NavCoder section for details.

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Update (11/17): Since installing this TCU (software version 29) in my E38 last January, I have encountered occassional phonebook pairing problems and slow-to-pair behavior with my old Andriod phone. Address book pairing is a known problem with some older TCU's.

Update (10/18): After almost 2 years of use, I had to replace my previous TCU after it suddenly stopped working (locked-up audio system and froze nav screen). The newer unit (software version 37) provides noticable improvements. Phone and address book pairing are immediate, and nav screens respond quickly. So far, I'm very pleased. I now recommend SW versions above 29 (see your TCU label).