I had a similar issue with my 05 Explorer, the wrench light indicates a "limp mode" so it looses power and shifts bad ect.. What was triggering it on mine was that my air filter was not seated right in the airbox and when it would rain, water would get by filter and hit the maf, then it would throw the code. But once I restarted the car the light would be gone and we could never find any codes in the system.
If you can recall the weather conditions when this happened? was it raining? Check your air box make sure every thing is tight and in the right spot in and around your air box.
I'm not sure what else causes the car to go into Limp mode.. Could be bad fuel.. not sure Google it.