WARNING: This page is about a different car, the 1994 Cadillac Fleetwood. However, it is still accessible from the selected car via links, so may be relevant.
Check for poor connections at PCM and at transmission connector.
Fig 1: Code 73 Schematic (Fleetwood) Pressure Control Solenoid
Fig 2: Code 73 Flow Chart (Fleetwood) Pressure Control Solenoid