The character of Jesse in Dom Torreto's team in the original The Fast and the Furious was interesting but didn't get much screen time.
In a conversation with Brian, he said something about having Attention Deficit Disorder and failing everything except math. Typically, students with ADD do struggle with academics (take it from me), but he mentioned an aptitude for math.
Combined with his avid interest in engines ("Engines just calmed me") (and computer-aided design) could it be possible that he would be more accurately described as being on the Autism Spectrum? Perhaps
Asperger's Disease Asperger Syndrome?
Given the time-frame of film and release, I would understand ADD being more accepted and familiar to audiences. If the film were remade today, would the diagnosis have changed?