F10er

Yes, they are all CAN communication errors for the DSC control unit. I would be checking the power and earth supplies to the DSC and also checking the PT CAN wiring between the DSC and DME, including unplugging them and visually checking the pins for corrosion. Have you got ISTA?

I think those are all CAN bus faults. If you put your VIN into mdecoder.com you can see what battery your car had from factory. As far as i know all E90s with a CCC or CIC came with a 90ah battery. I could be wrong though.

Have you checked the in the settings of the phone. You can turn bt audio off in there.

Sounds like a possible voltage issue. What is the alternator charge rate when engine is running? Also it's probably worth noting that your battery is too small. It should be a 90ah.

It's for the transport switch which is only used when the car is delivered from the factory to the dealer.

Is this any use?

I got my kit from Ebay UK. The hard thing about rebuilding it was not having any specs to go off for the pinion bearing preload, and the crownwheel and pinion backlash. BMW does not list those details anywhere. Got there in the end though.

The power management will selectively restrict power to any of these functions so although your seat heating works, it may still be restricting the blower speed. Start with the basics first like the battery. These cars MUST have a good battery of adequate size or there will be problems. Even a 70AH is too small really. I remember when i was working at a dealer when these cars were new, BMW were upgrading the 70ah batteries to a 90ah because the 70ah batteries were too small and causing a lot of issues. I would be getting rid of that undersize battery personally and installing a new one. It may not be the issue now, but it will give you problems eventually. Preventative maintenance. Also have you scanned the car for fault codes?

Screenshot from ISTA. If your battery is too small like you say it is, i would suspect this may be your problem.

If your car has an IBS sensor on the battery it might just be a weak battery. If the IBS senses the battery is weak, it will tell the power management in the car to restrict or sometimes completely deactivate power consumers like the blower motor, heated seats and heated rear window.

Topaz/bapmic is Chinese junk. Buy an OEM part and fix it properly. I personally wouldn't drive it.

Max counter clockwise position will have the valves closed so, yes it won't start because there is no air/fuel getting into the cylinder. What brand Valvetronic motor did you use?

Yep. Quite common for them to leak coolant.

The black plastic coolant flange on the back of the cylinder head is another weak point and a real pain in the arse to change in place. Might be a good idea to change that while the engine is out.

I would replace the whole engine.............with a 6 cylinder one. Those 4 cylinders are nothing but trouble.