My car (Honda Accord EX Coupe L4 2005) had this code (P0139 HO2S-12 (Bank 1 Sensor 2) Circuit slow response) 2 month ago. But i didn't see any symptom; so i erased the code because i thought that should have been the sensor getting old. This morning the same code came up. My question is What is most probable in this case a bad sensor or a leaking in the fuel injector system?
My car has 101000 miles.
My car has an automatic transmission.
This code indicates that the rear oxygen sensor is not properly reading the oxygen content and adjusting the air/fuel ratio as it is supposed to. This can be caused the by the sensor not working properly, the wiring to the sensor being damaged or broken or potentially an exhaust leak. I would recommend checking the following to correct this:
If you need some help with this, you may want to consider having an expert from YourMechanic come to your location to properly diagnose the trouble code and correct this problem.