1) Can this scanner help relearn the transmission and also help relearn the TCM for E46?

This scanner does not appear to support module programming/transmission adaptations on most vehicles, and the use of dealer level software is likely needed in your case (INPA/ISTA).

1) Will this reset airbag error light on 2005 BMW X5? 2) I have had to reset the steering alignment previously on my 1999 540i and each time I had to do it by the round connection under the hood, does this come with and adapter or can you purchase one?

This should work with the X5 no problem, and the round connector on e46 is technically a holdover from the previous diagnostics gen, you should be able to accomplish this with the Autel no problem.

1) Will this tool reset my oil maintenance reminder on the instrument panel of my 2021 Porsche 718 Cayman S? 2) Will this tool allow me to read transmission temperature on my 2013 Volvo S60 ? 3) Will this tool allow me to reset my electronic TCM on the automatic transmission of my 2013 Volvo S60 after a transmission oil change?

Will do all but reset the TCM on your 2013 Volvo S60. In that application The Autels would not be able to reset the TCM unfortunately.

How much is the annual free in year 2+ for this scanner?

Historically the update would be $99.

Will this unit scan domestic vehicles ( ford chevy)?

Yes, absolutely without issue

Hello, will this scanner require a subscription or is it just buying the scanner and that's it?

This scanner will function without a subscription, however, you can purchase a subscription to continuously be up to date with system updates. But this is not required.

Can this product code a new frm module? If not which one should i get to code it. Any recommendations? Mine is fried and idk what to do or where to take it

No, unfortunately this will not recode modules, depending on your year make and model you will likely need proprietary tools by the vehicle manufacturer in order to rest that module.

Can this unit perform air suspension diagnostic testing on a 2011 Mercedes GL550?

Yes, this scanner can read/interact with the air suspension module.

Does the Autel MX900 OBDII Scanner read over revs for Porsche 718 Thanks !

This model is unable to pull rev data from the DME.

Can this model code new fuel injectors on Mercedes?

Yes