Your car may have either Bosch or Denso brand O2 sensors. The best bet is to get a look at the original sensor and replace it with the OE brand. Get the proper plug-n-play version rather than the generic version that you have to splice the wires. I like Stockwiseauto.com for O2 sensors as they have the right stuff and generally decent prices.

Determine whether that fault code points to the upstream or downstream sensor. If you know which two wires* feed the Pre-heater then you should be able to measure infinite ohms at the disconnect pins. Also, if it’s a Pre-heater problem it will set a fault code by just turning on the ignition - you don’t even have to start the engine. (Apparently the Pre-heater starts heating when the ignition is turned on. It doesn’t wait for the engine to start.)

* I really miss those wiring diagrams that used to be available on the web.
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Current rides: 2005 Volvo S80 2.5T, 2003 Volvo V70 2.4NA, 1973 Volvo 1800ES (getting ever closer to road worthiness)