Notes On Intermittents
WARNING: This page is about a different car, the 1988 Cadillac Seville and 1988 Cadillac Eldorado. However, it is still accessible from the selected car via links, so may be relevant.
If code EO64 is stored as an intermittent code and customer complains of frequent loss of cruise control, drive vehicle while observing ECM data ED12 (vehicle speed). If speed display is erratic, check operation and integrity of vehicle speed sensor circuit.