Malfunction Indicator Lamp: Description and Operation

MALFUNCTION INDICATOR LAMP (SERVICE ENGINE SOON LIGHT)

Your vehicle is equipped with a computer which monitors operation of the fuel, ignition and emission control systems.
This system is called OBD II (On-Board Diagnostics-Second Generation) and is intended to assure that emissions are at acceptable levels for the life of the vehicle, helping to produce a cleaner environment. The "SERVICE ENGINE SOON" light comes on and a chime will sound to indicate that there is a problem and service is required. Malfunctions often will be indicated by the system before any problem is apparent. This may prevent more serious damage to your vehicle. This system is also designed to assist your service technician in correctly diagnosing any malfunction.

NOTICE:
If you keep driving your vehicle with this light on, after a while, your emission controls may not work as well, your fuel economy may not be as good and your engine may not run as smoothly. This could lead to costly repairs that may not be covered by your warranty.

NOTICE:
Modifications made to the engine, transaxle, exhaust or fuel system of your vehicle or the replacement of the original tires with other than those of the same Tire Performance Criteria (TPC) can affect your vehicle's emission controls and may cause the "SERVICE ENGINE SOON" light to come on. Modifications to these systems could lead to costly repairs not covered by your warranty. This may also result in a failure to pass a required Emission Inspection/Maintenance test.

This light should come on, as a check to show you it is working, when the ignition is on and the engine is not running. If the light doesn't come on, have it repaired.

This light will also come on during a malfunction in one of two ways:
^ LIGHT FLASHING - A misfire condition has been detected. A misfire increases vehicle emissions and may damage the emission control system of your vehicle. Dealer or qualified service center diagnosis and service may be required.
^ LIGHT ON STEADY -- An emission control system malfunction has been detected on your vehicle. Dealer or qualified service center diagnosis and service may be required.

IF THE LIGHT IS FLASHING
The following may prevent more serious damage to your vehicle:
^ Reducing vehicle speed.
^ Avoiding hard accelerations.
^ Avoiding steep uphill grades.
^ If you are towing a trailer, reduce the amount of cargo being hauled as soon as it is possible.
If the light continues to flash, when it is safe to do so, stop the vehicle. Find a safe place to park your vehicle. Turn the key off, wait at least 10 seconds and restart the engine. If the light remains on steady, see "If the Light Is On Steady" following. If the light is still flashing, follow the previous steps, and drive the vehicle to your dealer or qualified service center for service.

IF THE LIGHT IS ON STEADY
You may be able to correct the emission system malfunction by considering the following:
Did you recently put fuel into your vehicle?
If so, reinstall the fuel cap, making sure to fully install the cap. See "Filling Your Tank" in the Index. The diagnostic system can determine if the fuel cap has been left off or improperly installed. A loose or missing fuel cap will allow fuel to evaporate into the atmosphere. A few' driving trips with the cap properly installed should rum the light off.
Did you Just drive through a deep puddle of water?
If so, your electrical system may be wet. The condition will usually be corrected when the electrical system dries out. A few driving trips should turn the light off.
Have you recently changed brands of fuel?
If so, be sure to fuel your vehicle with quality fuel. Poor fuel quality will cause your engine not to run as efficiently as designed. You may notice this as stalling after start-up, stalling when you put the vehicle into gear, misfiring, hesitation on acceleration or stumbling on acceleration. (These continuous may go away once the engine is warmed up.) This will be detected by the system and cause the light to turn on.
If you experience one or more of these conditions, change the fuel brand you use It will require at least one full tank of the proper fuel to turn the light off.
If none of the above steps have made the light turn off, have your dealer or qualified service center check the vehicle. Your dealer has the proper test equipment and diagnostic tools to fix any mechanical or electrical problems that may have developed.