o2 Sensors stopped responding after disconnecting battery
 

Hello Mazda 3 Club,

I wish I could join under better circumstances, but I am at my wits end. Yesterday (12-11-17) I disconnected the negative battery terminal on my 2005 Mazda 3 in order to add some new lights. Fast forward in time to the completion of that project, I reconnected the battery and started the car. It ran rough as I expected it to after being disconnected, so I let it warm up, but the problem didn’t seem to go away. The car was consistently sluggish with a very rough idle, and I noticed an immense power loss. Unfortunately, these symptoms weren’t new to me. A few months ago I was having these same problems, so I diagnosed the problem and replaced the two o2 sensors, as they were unresponsive. Problem solved, car ran great again, up until yesterday when I disconnected the battery. According to the diagnostic codes, both o2 sensors are once again unresponsive ( codes P0134 and P0140). I have no idea why disconnecting the battery would cause the sensors to malfunction, but considering they aren’t more than a half year old, they can’t be bad already! I’ve tried disconnecting the battery again, I’ve reset the engine codes, I’ve unplugged the sensors and plugged them back in, but nothing seems to work. I expected the problem to fix itself, and while the symptoms seem to become minimal at times, the problem still persists. I don’t know what to do. Has anyone else experienced something of this nature? Please advise, and thank you!

Hi Damon! Did you figure out what was going on? I’m experiencing the exact same issue as you were. Any help will be appreciated.