I brought my new truck in for service as the check engine light came on. After diagnosis they were able to pinpoint the problem, had all the parts needed in stock, so I said go for it. Well after they took it apart they found another issue, didn't have that part. So they gave me a loaner car, with a promise they would have it fixed the next day after receiving the part.
Around noon the next day, I received a call that it was ready. I picked it up later that afternoon with a nice wash to the outside and no check engine light on. Thank goodness everything was still under warranty.