Note On Intermittents
WARNING: This page is about a different car, the 1995 Cadillac DeVille. However, it is still accessible from the selected car via links, so may be relevant.
Manipulate circuit No. 410 wiring, ECT sensor connector and PCM connector while observing PCM Data PD04. If engine coolant temperature jumps from normal reading to 298°F (148°C) or greater, repair intermittent short to ground on circuit No. 410. Remove and reconnect both ECT sensor and PCM connectors and retest before replacing any components. If wiring and connectors are okay, substitute a known good ECT sensor and retest.