I have turned the key to the on position, just before turning the engine over. Then I turned the key off. I did this three times, the third time leaving the key on to be able to read the odometer reading. All I saw was the odometer reading. The car "dinged" 5 times each time.
Then thinking that I should have turned the engine on then off, I did that 3 times and still the odometer reading just shows the number of miles driven.
I DID IT! Here are the codes:
P1684 and P0456