Q: P0139 HO2S-12 (Bank 1 Sensor 2) Circuit Slow Response - 2005 Honda Accord

asked by on

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:

  • Check and fix any exhaust leaks
  • Check for wiring problems (shorted, frayed wires)
  • Check the frequency and amplitude of the oxygen sensor (advanced)
  • Check for a deteriorating/contaminated oxygen sensor, replace if necessary
  • Check for inlet air leaks
  • Check the MAF sensor for proper operation

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.

Was this answer helpful?
The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details
  1. Home
  2. Questions
  3. P0139 HO2S-12 (Bank 1 Sensor 2) Circuit Slow Response - 2005 Honda Accord

Get an instant quote for your car

Our certified mechanics come to you ・Backed by 12-month, 12,000-mile guarantee・Fair and transparent pricing

Get a quote

What others are asking

Q: How long does it take to remove and replace a throttle?

Hi there If the throttle sensor is not working, it's most likely caused by an electrical issue; as opposed to a mechanical problem with the throttle body or other components. The best thing to do is have a professional mobile...

Q: How do you use the Maintenance Minder™?

The computer system on your car is pretty sophisticated and is capable of tracking many different services and maintenance requirements. It informs you of what’s due and when through the Maintenance Minder™ on the car. Here’s how to use it:...

Q: Shuddering, check engine light on. 2005 Saab 9-2X

Hello. It is possible that the previous repairs could cause this problem. It is also equally possible that the new problems are not related to the previous problems that you were having. If the timing belt is not on the...

Related articles

How Long Does a Distributor O Ring Last?
The distributor is part of the ignition system in your vehicle and its purpose is to route high voltage from the ignition coil to the spark plug. The spark plug then...
P0052 OBD-II Trouble Code: HO2S Heater Control Circuit High (Bank 2 Sensor 1)
P0052 code definition HO2S Heater Control Circuit High (Bank 2 Sensor 1) What the...
Rules of the Road For Iowa Drivers
Driving on the roads requires knowledge of the rules, many of which are based on common sense and courtesy. However, even though you know the rules in...