On-Board Diagnostics (OBD-II)
Your vehicle has a computer known as theon-board diagnostics system (OBD-II) thatmonitors the engine’s emission controlsystem. The system protects theenvironment by making sure that yourvehicle continues to meet governmentemission standards. The OBD-II systemalso assists a service technician in properlyservicing your vehicle.
When the service engine soonindicator illuminates, the OBD-IIsystem has detected amalfunction. Temporary malfunctions maycause the service engine soon indicator toilluminate. Examples are:
1.Your vehicle has run out of fuel—theengine may misfire or run poorly.
2.Poor fuel quality or water in thefuel—the engine may misfire or runpoorly.
3.The fuel fill inlet may not have closedproperly. See Refueling (page 155).
4.Driving through deep water—theelectrical system may be wet.
You can correct these temporarymalfunctions by filling the fuel tank withgood quality fuel, properly closing the fuelfill inlet or letting the electrical system dryout. After three driving cycles without theseor any other temporary malfunctionspresent, the service engine soon indicatorshould stay off the next time you start theengine. A driving cycle consists of a coldengine startup followed by mixed city andhighway driving. No additional vehicleservice is required.
If the service engine soon indicator remainson, have your vehicle serviced at the firstavailable opportunity. Although somemalfunctions detected by the OBD-II maynot have symptoms that are apparent,continued driving with the service enginesoon indicator on can result in increasedemissions, lower fuel economy, reducedengine and transmission smoothness andlead to more costly repairs.
Readiness for Inspection andMaintenance (I/M) Testing
Some state and provincial and localgovernments may haveInspection/Maintenance (I/M) programsto inspect the emission control equipmenton your vehicle. Failure to pass thisinspection could prevent you from gettinga vehicle registration.
If the service engine soonindicator is on or the bulb doesnot work, your vehicle may needservice. See On-Board Diagnostics.
Your vehicle may not pass the I/M test ifthe service engine soon indicator is on ornot working properly (bulb is burned out),or if the OBD-II system has determinedthat some of the emission control systemshave not been properly checked. In thiscase, the vehicle is not ready for I/Mtesting.
If the vehicle’s engine or transmission hasjust been serviced, or the battery hasrecently run down or been replaced, theOBD-II system may indicate that thevehicle is not ready for I/M testing. Todetermine if the vehicle is ready for I/Mtesting, turn the ignition key to the onposition for 15 seconds without crankingthe engine. If the service engine soonindicator blinks eight times, it means thatthe vehicle is not ready for I/M testing; ifthe service engine soon indicator stays onsolid, it means that your vehicle is readyfor I/M testing.
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2023 Mustang (CZG) Canada/United States of America, Vehicles Built From: 14-11-2022, enUSA, Edition date: 202209, First-PrintingEngine Emission ControlE67028 E67028
