It was not clear to me that you need to read the engine codes before they can be reset.

To read ENGINE/FUEL INJECTION/TIMING CODES,

Ignition in on position but starter not engaged. Dash panel lighted.

Test probe inserted in position 2. Push button for about a second and record the first three digit sequence. Write it down. When flashing light finishes the sequence, press the button for a about a second to display the next three digit code. When doing so causes a code to repeat, you are at the end. Press and hold the button for 6 to 10 seconds. Release. When the light comes on again, press the button again. The codes should now be cleared.

At this time, it is not clear to me whether you need to display each stored code only once or if you just need to be certain that all have been displayed at least once. I think that you can display the codes multiple times but I am not absolutely sure. You might need to test that and get back to us with the answer.

I thought that I could just reset the codes without reading them. I could not.