How many people can figure out what's going on in my Toyota's on-board computer? Even Toyota's techs had trouble reading their own code when the stuck accelerat

How many people can figure out what's going on in my Toyota's on-board computer? Even Toyota's techs had trouble reading their own code when the stuck accelerator issue happened. We're already in this black box hypothetical. I don't think its such a big change. I mean, can you audit the code in google's self-driving car? Who can?