I have a 2003 Ford Expedition.
the check engine light came on and when scan the codes B 1600, B 1602, P 0171, P
0174 came up. What do those mean?
B1600 and 1602 are PATS (Passive Anti-Theft System) Try another key. Actually something is really whacky if it starts with those codes. See http://b1600.enginetroublecode.com/ford-expedition and............. http://www.ford-trucks.com/forums/812980-b1600-1602-codes.html
P0171 and P0174 is lean, both banks. Could be faulty MAF (or just dirty,) the Mass Air Flow sensor measures the air flow going in to intake. Or a vacuum leak. Lean running can damage your catalytic convertor in a short time. Look for vacuum hoses fallen off, especially PCV See http://www.obd-codes.com/p0174 - http://engine-codes.com/p0171_ford.html
Search Ford Expedition Questions
Ford Expedition Experts