The 1957 Chevy Nomad is one of the finest vehicles ever made my mother drives one that is in perfect condition.

Which sentence error does the text above make?

The sentence above should be divided into two sentences. There should be a period after the word "made." So the correct sentence should be like this:

The 1957 Chevy Nomad is one of the finest vehicles ever made. My mother drives on that is in perfect condition.