1995 GMC Jimmy Owner's Manual - Page 125

indicated by the system before any problem is apparent, which may prevent more serious damage to your vehicle. This system is also designed to assist your service technician in correctly diagnosing any malfunction. The "SERVICE ENGINE SOON, light should come on, as acheck to show you it is working, when the ignition is on and the engine is not running. This light will also come during a malfunction in one of two ways: 0 Light on steady - indicates a system malfunction has been detected. Drive the vehicle to the dealer for service at your first opportunity. Light flashing - indicates a misfire has been detected which may damage the emission control system. The damage may be reduced by lowering the vehicle speed, reducing the amount of cargo being hauled or trailered, avoiding hard acceleration, or by avoiding steep uphill grades. If these actions are effective, the light will stop flashing and remain on steady, Drive the vehicle to a dealer for service. If the light continues to flash, stop the vehicle. Wait for asteady light to come on, then drive the vehicle to a dealer for service. 0 These following conditions also may cause the "SERVICEENGINE SOON' light to come on: Low Fuel/Out of Fuel - As the vehicle starts to run out of fuel the "SERVICE ENGINE SOON, light may come on as a result of an engine misfire. Filling your gasoline tank should correct this condition. Make sure to install the gas cap fully. It will require a few driving trips to turn thelight Of f. Poor Quality Fuel - Be sure to fuel your vehicle with qualityfuel. Your engine may not run efficiently on poor fuel. Poor fuel may cause stalling, hesitation or misfire. These conditions may go away when the engine is warned-up. However, poor quality fuel may cause the "SERVICE ENGINE SOON" light to come on. Have a dealer check the vehicle. If no problems are found, you may want to change to another brand of fuel. Driving Through Standing Water - Driving your vehicle through puddles of deep standing water may result in a temporary misfire condition. This condition will usually correct itself shortly after the electrical system dries out. It will require a few driving trips to turn the light off. 2-73