FORD 2003 Mustang v.3 - Manual (Page 186)

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.
Maintenance and Specifications
186