I've had an intermittent P2097 "post Cat too rich b2" code on my Outback for the past couple of weeks. An ECU reset has got rid of it for a few drives, but they've mostly been too short to bring it up to full temperature and it may not have gone to the closed loop operation in that time (it's cold here and full temp takes several miles to reach). I understand from searching here that either pre or post-Cat O2/AFR sensor failing could trigger the error.
I've replaced the air-filter and cleaned the MAF, as the filter was just about due, which got rid of the CEL for a week or so. So right now I'm assuming that one of the two original O2 sensors (123k miles, non-Cal car) is fading out, but I can't tell which one with FreeSSM/RomRaider. What are the expected voltages in closed loop, fully up to temperature operation for the two sensors? Is that the best way to diagnose?
I've replaced the air-filter and cleaned the MAF, as the filter was just about due, which got rid of the CEL for a week or so. So right now I'm assuming that one of the two original O2 sensors (123k miles, non-Cal car) is fading out, but I can't tell which one with FreeSSM/RomRaider. What are the expected voltages in closed loop, fully up to temperature operation for the two sensors? Is that the best way to diagnose?