Diagnostic Aids:

WARNING: This page is about a different car, the 1995 GMC Sonoma. However, it is still accessible from the selected car via links, so may be relevant.

DTC 2 will set if 4-pin connector is disconnected and ignition is turned on or 6-pin connector is plugged in before 4-pin connector with ignition on.
DO NOT pierce connectors, wires, seals, or insulation during testing. Doing so will lead to corrosion and failure of wiring and terminals.