We had a couple of codes on my son-in-law's 2000 Expedition (P1xxx), 5.4, with close to 200,000 Miles. Replaced the MAF and codes cleared. Specific codes were replaced with a P1000. In researching this, it appears to be waiting on the engine diagnostics to complete.

Any experiences out there? Will it clear itself with time? Do I need to address it now and if so, How?

Thanks

 

Did you disconnect the battery when replacing the MAF? (at least 15 min.)

Sounds like that is all that needs to be done to clear the code. It may eventually go off. There are a certain number of drive cycles required for the computer to reset itself. Disconnecting the battery will expedite the process a bit.