Just out of curioisity, I bought second hand VW which had fault code for air quality sensor. Bought new sensor and decided to open and see whether I can find any obvious reason why it was broken. First of all I was amazed that the connector pins were not soldered. I was able to measure 1 ohm resistance from the pins, but I doubt that is the reason. Noticed that three of the very fine golden wires that go to the square sensors were detached. I'm not sure did I broke them when disassembling or were these detached in the first place. What do you think what was the reason for this being broken?