Dunno about the 98's, but at least on my '02, there would at the very least be trouble codes set and check engine lights lit, and engine at very least would poorly driveable - I seriously doubt all would appear normal if the wire was completely severed.
Otherwise, a simple VOM continuity check from each side of the connector point would show if the wire was intact. You can do that by using a pair of needles or pins on each side of that point, piercing the outer insulation to the inner conductor to take a meter reading.