[clairekathryn]

I've been reading this forum for 2 years now but only just now joined so I am a new member, please be patient with me if you can!

I'm looking for advice.

My 2008 BMW X3 (E83) 3.0SI would not start and so the repair shop I go to replaced the starter as it was under warranty, but that did not fix the issue.

They say the issue is that the transmission cannot communicate with the engine/motor and that a replacement mechatronic unit is the only fix.

They had quoted me $3,076 for a used transmission control unit which I agreed to, but then they found out that the transmission control units cannot be used in your vehicle due to factory programming that cannot be removed from the used modules. The lowest price they have seen for a new compatible transmission control unit for my vehicle is $3,100 + additional misc. parts and labor to install. That increases the overall bill from the original price of $3076 to $5,280, which is way over budget.

What would you do in my situation? The rest of the vehicle (including the engine) is in great shape and it has new starter, control arms, tires, etc.

Is parting it out something that you would advise?

I just don't know what to do as I truly love this car but can't afford to fix it and I want to do it justice and be respectful to other BMW owners who may want it or its parts.

Here's the exact diagnosis:
"Vehicle will not start but has power when turning ignition on. Performed diagnostic scan and found no communication with
EGS (transmission control unit). Performed BMW ISTA test plan and ran through wiring checks and initial diagnostic
procedures. All wiring looks OK, power and ground present. EGS control module is dead and must be replaced. Module is
integrated into the valve body, or mechatronic unit, located inside the transmission."

[richardodn]

First of all, I'm not well versed in this area but I did do a bit of searching to see if I could make sense of what's going on. I could very easily have gotten something wrong, but here's what I understand.

The 2008 has the GM GA6L45R transmission. In this system, the EGS (electronic gear selector) unit is integrated with the mechatronic valve body. The EGS computer is paired to the engine's DME (digital motor electronics). The standard BMW tools do not allow replacement with a used unit because the pairing can not be overwritten. This means you need to replace it with a new unit that has never been paired. This is where you're currently sitting.

I see two options. First is repair of your existing module. Basically since the unit is not actually replaced, no coding needs to happen. The second involves initializing the data in the replacement used unit with data from the old one. Neither of these can be done by your shop since they lack the specialized tools and knowledge.

I did a search on "bmw 3.0si egs tcm repair"

This company claims to be able to repair most units. Alternately, they can clone the old one into a replacement. https://ecuteam.com/bmw-auto-compute...cm-egs-module/
I'd give them a call and make sure they can handle the unit in the GM transmission.

This Ebay vendor has a remanufactured unit and can program the VIN number for you. https://www.ebay.com/itm/153180245201
At $850 for the unit, this may be the easiest way. Note that they are in China, but they also have great feedback.

I'm sure there are other vendors out there. This should get you started on some alternate paths.