If your car or truck is less than 15 years old, chances are it has a computer.
You can't just plug in your keyboard and monitor and talk to it, but it does control
many engine functions, and it remembers what isn't working quite right. The earlier
ones would output a series of numerical codes that could be read with a simple
device sold for under $20. It plugged into the diagnostic output plug and gave you
the numbers with a single flasing LED, or an optional beep. Blink-blink-blink-pause-
blink-blink-longer pause
would be 32. Look up 32 in the book and it would tell you,
for example, that the oxygen sensor was fried.
Not a bad system, though a bit primitive. I was just about to devise an interface with
my Atari 800xl and write a basic program to go with it. A couple of years later, though,
carmakers decided too many people were fixing their own cars and changed the
diagnostic output so it could only be read by their dealers' expensive diagnostic machine.


For those of us who can't afford to have things done for us, and even enjoy being
able to repair our own devices under the shade tree on Sunday afternoon, this is
a major setback. However, someone with the right equipment could put the wrenches
back in the hands of the people and make a few bucks besides.

First, the car owner needs an interface cable to plug into the vehicle's diagnostic
output (these might be manufacturer-specific), and connect to a PC serial port.
Second, if the diagnosis is done online, the PC would need a small program to read
the incoming data and send it to the diagnostic site on the web.

The online auto doctor then runs the data through a diagnostic reader and emails back a
This could be enhanced with an agreement with an auto-parts chain to list the price
and availibility of any part that needs replacing.
Commissions from this and sales of the PC interface (or MAC interface) would
probably make charging for the online diagnosis unnecessary.

If anyone makes a fortune with this idea, remeber that you were inspired by