Note On Intermittents
WARNING: This page is about a different car, the 1993 Cadillac Seville and 1993 Cadillac Eldorado. However, it is still accessible from the selected car via links, so may be relevant.
Manipulate wiring on circuit No. 410, coolant sensor and PCM connector while observing PCM parameter PD04. If failure is induced, coolant temperature will jump from its normal value to shorted reading of 148°C or greater. Disconnect and reconnect coolant sensor and PCM connectors, and ensure they properly latch. If wiring and connectors are okay, substitute a known good sensor, and retest.