2003 Oldsmobile Alero Owner's Manual - Page 137

This system is called OBD I (On-Board 1 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 or CHECK ENGINE light comes on 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. 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 on 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. Notices If you keep driving your vehicle with this light on, after a while, your emission controls may not workas well, your fuel economy may not be as good and your engine may not run as If the Light Is Flashing smoothly. This could lead to costly repairs that may The following may prevent more serious damage to not be covered by your warranty. your vehicle: Notices Modifications made to the engine, Reducing vehicle speed. transaxle, exhaust, intake or fuel system of your vehicle or the replacement of the original tires with Avoiding hard accelerations. other than those of the same Tire Performance Avoiding steep uphill grades. Criteria (TPC) can affect your vehicle's emission controls and may cause this light to come on. If you are towing a trailer, reduce the amount of Modifications to these systems could lead to costly cargo being hauled as soon as it is possible. repairs not covered by your warranty. This may If the light stops flashing and remains on steady, see "If also result in a failure to pass a required Emission the Light Is On Steady'' following. Inspection/Maintenance test. 3-32