Not a big deal really. The hardest problem I have with O2 sensors is locating the one giving the trouble if you have no diagrams.

The low voltage signal usually means the "heater" in the sensor is defective or open. The heater allows the sensor to warm up faster, to allow the ECM to control the fuel mixture quicker and more accurate. Also it keeps the sensor heated to the proper temperature when idling a period of time when the exhaust runs to cool for an accurate reading.

Until the sensor warms up, the system runs on defaults (open loop). I would think the Crossfire is the same...

Good luck, James