This is part of a bulletin covering eliminating the message in various models. HTH
1991 Eldorado and Seville with Computer Command Ride (CCR): Refer to the Service Manual page 8D-12. Set the BCM override value BS09 to 0 by using the warmer and cooler buttons. Store this value by pressing the Econ button on the climate control panel and the Instant Econ button on the Fuel Data/Drivers Information Center for about five seconds. The new value will be stored even through the indicator does not flash. Remove the key from the ignition. Disconnect both battery cables from the battery. When both cables have been disconnected, touch the ends of the cables together and hold for five seconds. This will discharge the capacitors in the system and allow the system to perform properly when the battery cables are reconnected. Advise the customer they will have to reset all radio stations and clock.