First of all, tranny repairs do NOT have to be done at a dealership. This tranny is used in other cars, like the Toyota, and can be repaired for a few thousand US dollars at a tranny shop.

Now, the good news. She should find a shop that can read the Volvo codes as it is probably the ABS module that broke. The speed signal goes through the ABS before it goes to the TCU and ECU. A TCU that does not know the speed will generate an immediate error code and slip the tranny in limp home mode.

More good news. There are outfits that will repair the existing ABS module. Some, like xemodex will not require dealer software, but someone will have to remove the module and ship it. xmodex has mailing addresses in the USA and Canada.
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My name is Klaus and I am a V♂lv♂holic