Hi i just encountered a problem with my truck. I have a 2002 f150 5.4. The service engine light came on but scanners wont read the codes. Truck runs and drives good , no noticeable problem yet. Just bothers me having that light on. Any suggestions to why it wont read the codes?

 

What brand of scanner are you using?
Check if you have power at pin #16 of the diagnostic plug.