I believe this is how you do it, turn the key on to acc. don't start the engine. turn the key back to off. Do this three times, but on the third time leave it in the acc position and it will bring up codes.
Other things you can do are a dash light check, hold the odometer reset button while turning key to acc. and your dash will light up like a christmas tree.
With the key on acc and the engine off and your odometer on total miles press and hold the odo reset button for about 6 seconds and this will show total hours for engine run time
Shawn