I will show you today how to get Engine Code and Reset Engine Light on a Nissan 300zx:

1. Remove the carpet and wood cover in the passenger side

2. Remove ECU. on the side you will find a selector

3. turn egnition key to ON (not start)

4. on the ECU, move selector clockwise wait 5 seconds and turn back

5. Look at the "CHECK ENGINE" Ling, it will give you the codes. the first code will be slow, and the second code will flash faster

6. to reset, step 4 and 5 three times, turn ingintion off and then on, when you turn it back on, the check engine light will be gone.