people don't erase the codes from the ecm take it to the dealer there could possibly be a tsb on it just saying.....................
Dealers can pull up codes even if they disappear. My truck is the reason people are getting updated software. Check engine light came on 3 times, but the last time it ended up shutting itself off before I got to the dealership and they were able to pull it up.
These trucks have black boxes in them. They're watching every move you make, like the GTRs.