Hey guys - just bought this 08 535i and there is an SOS malfunction that is affecting (killing) bluetooth and voice commands connectivity in the car. Radio and AUX still work.
I have an 05 525i that has a dead tranny but BT / voice command / radio etc works fine. I've read that the SOS problem could be a bad TCU or SOS module and wonder if I have viable replacement parts in the 525?
I've also heard that the SOS error can be bypassed using a fiber optic loop and that can help narrow down which module is bad.
Can someone help me step-by-step the troubleshooting? I *don't* have the loop, but they are cheap on amazon ($20 for a male / female set). I also don't have a coding platform (NCS Expert or any of the other stuff) but I'm not afraid of doing any of this stuff to get under the hood and learn more about doing my own repairs.
Any help is appreciated.
Working on the exact same condition as we speak on a 645 convertible. The way I understand it, you start at the CCC, check and see if you have optic light at the back of it. Then the CD changer, then the TCU, then the trunk components. My understanding is the TCU controls the SOS phone function. You jump that with your Female MOST loop. The TCU module on mine was located behind the back seat on the drivers side. Lift up the rear seat bottom, remove two 10mm body nuts then lift off the back of the seat. Yours might be in the trunk on the drivers side.
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