The eBay TCU part you found is only for an E60 5 Series and E63 6 Series. It will not work in your car.

It sounds like you could have a bad TCU. Though, it could just be that the electrical contacts for the SIM card are dirty. You might try disassembling the TCU and cleaning the SIM electrical contacts with alcohol.

If you have to buy a new TCU, look specifically for one of these part numbers: 84.11-6 946 011, 84.10-6 978 533, or 84.10-9 187 926.

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