Diagnostic Aids
WARNING: This page does not describe the selected car, but rather 35 other vehicles, including the 1992 Pontiac Trans Sport, 1992 Oldsmobile Silhouette, 1992 Oldsmobile Bravada, 1992 GMC Yukon, and 1992 GMC Vandura Special. However, it is still accessible from the selected car via links, so may be relevant.
An intermittent may be caused by a poor connection, rubbed-through wire insulation or a broken wire inside insulation. Check PCM harness connector for backed out terminals. Connect a DVOM between affected terminal and ground. Wiggle related wires and connectors while watching DVOM for voltage reading change. Ensure coolant temperature sensor is not mis-scaled. See Code 15 in G - TESTS W/ CODES article in this section. Ensure engine cooling system is operating normally.