I was having problems with my O2 sensor on my 99 Civic Si, so I swapped it out for a 4 wire universal today. When I put it in I got a CEL Code 41. All the wires are soldered. So I figured I would check the resistance across the stock O2 vs the replacement. What I found was that the stock O2 sensors had 13.5 Ohms of resistance across the heater wires and the universal replacement had 3.0 Ohms. Do you think that this may be what is causing the CEL 41? Any other thoughts?