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.
With key on, engine off, manipulate wiring and connectors while observing ECM Input EI78. If EI78 cycles to "LO" at any time, repair intermittent open.
Review snapshot data parameters stored with this code to verify failure. If failure is verified, check and repair intermittent wiring connections or sensor.