So, right before I left for my last work trip, I went out to take the GP2 for a drive and the check engine light came on at start up. So I plugged in the OBD2 and turned on Dashcommand. No error codes were thrown. Then I poked around in Dashcommand (This is still new to me) and found what appears to me to be issue: If you look at the pic below, Oxygen Sensor has a "!" next to it. But no details. Then, I left to get on a plane.... two weeks later, I'm now back at it and wanted to see if I could get more information regarding the using OBD Fusion as it provides more information. I pull that information and am now doing some research to confirm its my Oxygen Sensor(s). I had an issue at MOTD with an Oxygen sensor and had it changed by Detroit Tuned Tent (Thanks Chad) but I don't remember which one. I think I will most likely be able to visually figure that out... but if memory is correct its the post cat one (My car doesn't have a cat). However when I look at the diagnostics I see some interesting things. Again, this is new to me so I'm doing some research, but figured I would go ahead and post this should someone know off the top of their head. First thing: No Codes and Ready for Emissions testing.. which that seems odd if you have a Yellow check engine light. Mode $05 - Shows both sensors Mode $06 - On-Board Monitoring does not seem to show Sensor 1 (the wideband sensor). I would think it would at least show sensor one with no values. Also Sensor 2 seems to be incomplete regarding the check and the value is at the top of the range. So I "see" this as an issue, but researching to see if it is or just my lack of knowledge in this area. Mode $01 Powertrain Diagnostic Data When I look at the sensor value's it shows both sensors so they are reporting in... which does confuse me regarding the above image. I also need to look up the values to see if they are in range or not. I find it odd that both sensors are reporting in, neither sensor check is complete, the monitoring doesn't show sensor 1 while the car clearly see's it (that said, maybe it's not monitoring it). Ultimately, due to both sensors not completing their checks, reporting in, but 1 sensor not being monitored (wideband).. I wonder if it's something else. 1) My Next step is to do some more research on what should be showing up (should both O2 Sensors?). 2) What are the proper values 3) What it means for the checks to show up as incomplete. If anyone is familiar with this type of situation, let me know. Otherwise as I do more research I'll update this thread.