Hello all,

I have a 2005 civic with no mods and 50k I recently recieved an error code for p0139 which is - Oxygen Sensor Circuit Slow Response (Bank1, Sensor2)
have looked at the wiring on the oxygen sensors and it all looks good so I am just goign to replace it, so my question is,

when I am at the front of the car looking at the engine there is 1 oxygen sensor that is right on the topside of the exhaust manifold and there is wires leading to one on the bottom side of the manifold but you cant really see it unless you are under car, so which sensor is throwing this code? sensor 2, is it the one of the top or bottom of the exhasut manifold? any help would be great.thanks

 

Be sure to reset the ECU to make sure the code repeats prior to replacing sensor.

P0139 is for the secondary O2 sensor, which is located after rather than before the catalytic converter with respect to exhaust flow. This is the O2 sensor located at the bottom rather than top of the exhaust manifold (see part #6 in diagram).

 

Great thanks for posting that diagram, how do I reset the ECU? unhook battery?

 

Remove fuse 6 under the hood for 1 minute and then reinsert.

 

does anyone by chance have a diagram showing the fuse panel numbers and locations. unfortunately my civic did not come with the owners manual and I cant find anything on the internet, just need to know which fuse is # 6. so that I can reset the ECU. TIA

 

#6 is a 15A fuse.

 

Ron you the man. Thanks Again

 

another stupid question. I took out the #6 fuse while the car was off and the error code came right back. so do I pull the #6 fuse while the car is running? so for the silly question, this is my first car with a computer. thanks

 

it is?
what were you driving before?

 

This outcome verifies that the secondary O2 sensor is in fact bad. Replacing the sensor should solve the problem.