1995 GMC Suburban Owner's Manual - Page 336

Engine Control Module System Gasoline Engines This system has an oxygen sensor (OS) that helps keep your engine's air-fuel mixture at a proper level. Use only unleaded fuel in your vehicle. If you use leaded fuel, you could damage your oxygen sensor (OS) and three-way catalytic converter. Diesel Vehicles Below8,500 (3 850 Kg) GVWR This system monitors engine speed and throttle position. It adjusts exhaust gas recirculation to limit emissions. Malfunction Indicator (SERVICE ENGINE SOON) Light The Malfunction Indicator (SERVICE ENGINE SOON) Light on your instrument panel lets you know when your emission system needs service. The light will come on briefly when you start your engine to let you know that the system is working. If it does not come on when you start your engine, or if it comes on and stays on while you're driving, your system may need service. Your vehicle should still be driveable, but you should have your system serviced right away. Secondary Air Injection Reaction (AIR) System (Gasoline Engines) You may have this system. It has a control valve thal will direct air to where it is needed. If the AIR system needs service, your Malfunction Indicator (SERVICE ENGINE SOON) Lamp on your instrument panel will come on. Tires We don't make tires. Your new vehicle comes with high-quality tires made by a leading tire manufacturer. These tires are warranted by the tire manufacturers, and their warranties are delivered with every new vehicle. If your spare tire is a different brand than your road tires, you will have a tire warranty folder from each of these manufacturers. 6-54