2003 Chevrolet Tahoe Owner's Manual - Page 110
2003 Chevrolet Tahoe Manual
Page 110 highlights
Starting and Operating Your Vehicle New Vehicle Break-in Notice: Your vehicle doesn't need an elaborate "break-in." But it will perform better in the long run if you follow these guidelines: Keep your speed at 55 mph (88 km/h) or less for the first 500 miles (805 km). Don't drive at any one speed- fast or slow - for the first500 miles (805 km). Don't make full-throttle starts. Avoid making hard stops for the first200 miles (322km) or so. During this time your new brake linings aren't yet brokenin. Hard stops with new linings can mean premature wear and earlier replacement. Follow this breaking-in guideline every time you get new brake linings. Don't tow a trailer during break-in. See "Towing a Trailer" in the Index for more information. Ignition Positions With the key in the ignition switch, you can turn the key to four different positions. C A L 2-2 1 A (LOCK): This position locks your ignition and transmission. It's a theft-deterrent feature. You will only be able to remove your key when the ignition is turned to LOCK. B (ACCESSORY): This position lets you use things like the radio, power windows and the windshield wipers when the engine is off.