After driving at highway speed for 10 or more miles with A/C on, when slowing down A/C turns off, resurculate light comes on, idle speed goes up to 1500 rpms. The only way to rset is to turn engine off and on. The system returns to normal immediatly until driving at highway speeds and slowing down when A/C again fails. Problem has be occurring for over 2 years and service has not been able to identify source, not error codes but occasionally service idle control system while be displayed.[:'(]
keywords: cadillac deville, cadillac, new cadillac's