I have an I phone. Downloaded app. Having problem connecting to vehicle. Need help.

When my mobile phone was having charging problems I downloaded a free app called 'Ampere'. This lets you see what's going on during the charge. Soon became apparent that my problem was the charging lead. A new charger and lead sorted the problem.
Charging from the mains is preferable to a USB point and charging in "Power Off" mode speeds things up.

Because there aren't any codes like you have there $7e8 ,where did you pull this from ? What year , make and model vehicle .

If the app is not supported then you are out of luck and can't use it. That is just how they built the car and you have no control over the decisions about this.

Can you play music on your cell phone? I have 412 songs on mine I loaded them all on my cell with my computer and a USB cable connected to my phone. I have an application from the phone's website(LG) in my case. It allows me to get music , pictures and video on and off my phone. Way easier than trying to load it with blue tooth . Try going to your phone's website to see if they have the software to do it.

When you have an eve app code when you have to reset the computer this can't be accomplished without having a advanced OBD two diagnostic tool some vehicles will reset after multiple key turns and starts but you didn't tell me what kind of vehicle you have

I would consider it unlikely unless there is a connection from the blue tooth unit receiver in the car and the ECM unit . Some vehicles can be traced by this connection of the audio telecommunications units installed but it would take a dedicated person to set such a control in position. It has been long considered a wish from law enforcement agencies to be able to turn off the ignition of pursued vehicles but as yet technology has not reached that stage of secure operations.

The check engine light should come on along with the rest of the warning lights as a test when you turn the key switch on.
They should then go off once the engine starts.

Common fault on FORD
Usually due to a poor connection in the YELLOW PLASTIC CONNECTOR underneath the passenger seat.
Just push it together properly and it should clear the AirBag fault