To check the codes, turn your key to the on position, then off position, do not start it or crack it, just turn it on and off 3 times, wait a second, and your check engine light will start to blink. If it blinks 1 quick blink, then the first number is a 1, then it will pause for a sec or 2, then start blinking again, if it blinks 3 quick blinks then the second number is a 3, so your code will be 13. After the first code it will pause for a few seconds longer and start to blink again. You will know the codes are done, when you get code number 55, that means its done.