FORD 2004 Expedition v.3 - Manual (Page 315)

Exhaust leaks may result in entry of harmful and potentially
lethal fumes into the passenger compartment.
Do not make any unauthorized changes to your vehicle or engine. By
law, vehicle owners and anyone who manufactures, repairs, services,
sells, leases, trades vehicles, or supervises a fleet of vehicles are not
permitted to intentionally remove an emission control device or prevent
it from working. Information about your vehicle’s emission system is on
the Vehicle Emission Control Information Decal located on or near the
engine. This decal identifies engine displacement and gives some tune up
specifications.
Please consult your Warranty Guide for complete emission warranty
information.
On board diagnostics (OBD-II)
Your vehicle is equipped with a computer that monitors the engine’s
emission control system. This system is commonly known as the On
Board Diagnostics System (OBD-II). This OBD-II system protects the
environment by ensuring that your vehicle continues to meet
government emission standards. The OBD-II system also assists the
service technician in properly servicing your vehicle. When the Check
engine/Service engine soon light illuminates, the OBD-II system has
detected a malfunction. Temporary malfunctions may cause your Check
engine/Service engine soon light to illuminate. Examples are:
1. The vehicle has run out of fuel. (The engine may misfire or run
poorly.)
2. Poor fuel quality or water in the fuel.
3. The fuel cap may not have been securely tightened.
These temporary malfunctions can be corrected by filling the fuel tank
with good quality fuel and/or properly tightening the fuel cap. After three
driving cycles without these or any other temporary malfunctions
present, the Check engine/Service engine soon light should turn off. (A
driving cycle consists of a cold engine startup followed by mixed
city/highway driving.) No additional vehicle service is required.
If the Check engine/Service engine soon light remains on, have your
vehicle serviced at the first available opportunity.
2004 Expedition (exd)
Owners Guide (post-2002-fmt)
USA English (fus)
Maintenance and Specifications
315