1997 Pontiac Grand Prix Owner's Manual - Page 144

Check Tire Pressure Light With the check tire pressure system, after you've driven 10 to 20 miles (15 to 30 km) the CHECK TIRE PRESS light will come on if the pressure in one tire becomes at least 10 psi (69 kPa) higher or lower than the other three tires. Mal€unctisn Indicator Lamp (Service EngineSoon Light) Your Pontiac is equipped with a computer which monitors operation of the fuel, ignition and emission control systems. CHECK TIRE PRESS SERVICE ENIGINIE SOON When the CHECK TIRE PRESS light comes on, you should stop as soon as you can and check all your tires for damage. (If a tire is flat, see "If a Tire Goes Flat'' in the Index.) Also check the tire pressure in all four tires as soon as you can. See ''Inflation - Tire Pressure in the Index. The light will stay onuntil you turn off the ignition or press the CALIBRATE TIP9 PRESS button. See "Check Tire Pressure Syst? ." in the Index. If the anti-lock brake system warning light comes on with the CHECK TIRE PRESS light, the check tire pressure system isn't working. See your Pontiac dealer for service. (Also, see "Anti-Lock Brake System Warning Light in the Index.) This system is called OBD I1 (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. (In Canada, OBD I1 is replaced by Enhanced Diagnostics.) The SERVICE ENGINESOON 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 yourservice technician in correctly diagnosing any malfunction. 2-70