Engine Oil Life Monitor, Indicator and Index

All Cadillacs are equipped with an Engine Oil Life Index (EOLI). It uses information received from the Powertrain Control Module to calculate the percentage of oil life remaining at any time. The information that is used to calculate the percentage is:
^ Miles driven since last reset.
^ Coolant temperature.
^ Engine revolutions.
^ Vehicle speed.

The percentage of oil life remaining can be displayed on the Fuel Data Center at anytime by pressing the RANGE and FUEL USED keys simultaneously. A number from 100 (new oil) to 0 (oil needs to be changed) will be displayed as long as the two keys are pressed. The previous display will return when the keys are released. The CHANGE OIL SOON telltale will light for a bulb check each time the ignition is cycled to ON. It will also light for 20 seconds whenever the ignition is turned ON and: (A) the oil life remaining is less than 10% or; (B) 7,500 miles (12,500 km) has been driven or; (C) 12 months have elapsed since the last reset. The 20 second telltale light is the reminder to change the oil soon.
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RESETTING THE ENGINE OIL LIFE INDEX;
Reset the EOLI after each change by pressing the RANGE and RESET keys on the Fuel Data Center for 5 to 60 seconds. Release key. The indicator will automatically reset to 100. THE CHANGE OIL SOON TELLTALE LIGHT WILL FLASH FOUR TIMES TO INDICATE THAT IT HAS RESET TO 100.
The oil change intervals determined by the EOLI will usually fall at, or between, the two recommended alternative intervals of 3,000 miles (5,000 kilometers) and 7,500 miles (12,500 kilometers), but could be shorter than 3,000 miles (5,000 kilometers) under some very severe driving conditions. The system will also indicate the need for an oil change if 7,500 miles (12,500 kilometers) or one year has passed since the last oil change. If the EOLI does not indicate the need for an oil change after 7,500 miles (12,500 kilometers) or one year, or if the EOLI display fails to appear, the oil should be changed and the EOLI system should be serviced. The EOLI will not detect excessively dusty conditions or engine malfunctions which may effect the oil. If you drive in dusty areas, change the engine oil after every 3,000 miles (5,000 kilometers) or 3 months (whichever comes first), unless instructed to do so sooner by the EOLI. Also, the EOLI does not measure the oil level. Therefore, the owner should check the oil level at each fuel fill.