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). The OBD-II system protects the
environment by ensuring that your vehicle continues to meet
government emission standards. The OBD-II system also assists your
authorized dealer in properly servicing your vehicle. When the
Service
engine soon
indicator illuminates, the OBD-II system has detected
a malfunction. Temporary malfunctions may cause the
Service engine
soon
indicator 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—the engine may misfire or run
poorly.
3. The fuel cap may not have been securely tightened. See
Fuel filler
cap
in this chapter.
4. Driving through deep water—the electrical system may be wet.
These temporary malfunctions can be corrected by filling the fuel tank
with good quality fuel, properly tightening the fuel cap or letting the
electrical system dry out. After three driving cycles without these or any
other temporary malfunctions present, the
Service engine soon
indicator should stay off the next time the engine is started. A driving
cycle consists of a cold engine startup followed by mixed city/highway
driving. No additional vehicle service is required.
If the
Service engine soon
indicator remains on, have your vehicle
serviced at the first available opportunity. Although some malfunctions
detected by the OBD-II may not have symptoms that are apparent,
continued driving with the
Service engine soon
indicator on can
result in increased emissions, lower fuel economy, reduced engine and
transmission smoothness, and lead to more costly repairs.
2008 05+ Mustang
(197)
Owners Guide (post-2002-fmt)
USA
(fus)
Maintenance and Specifications
264
