f3 check engine display

2017 f3 with less than 20 miles on it check engine display come on book said pull key 20 seconds {already tried} the code retrieval posted here isn't working we bought this from a guy who sold it with 8 miles on it he scared himself on a corner by a cliff because of no hand brake, any way yes we have warranty but we live 200 mi from dealers so if it's something simple i will take care of it my self any easy checks and how to get the codes

First thing I would check it battery voltage. If it sat for a long time it could have weakened the battery. Voltage and load test will at least rule this out.

I will check that but it was on a tender