Hey guys,

My car is throwing a CEL P0139 so I used my CarMD and it said "
This fault code indicates the Comprehensive Component Monitor (CCM) has detected that the amount of time between changes in the signal from the Oxygen Sensor (O2S) (Bank 1, Sensor 2) exceeded the maximum expected time period. The O2S is the principal sensor in the fuel mixture feedback control loop. The vehicle’s computer uses the signal from the O2S to adjust fuel delivery to compensate for “lean” or “rich” fuel mixture conditions. The CCM monitors the signal output from the O2S and verifies the signal is within acceptable limits.It also said the reccomended fix would be to replace the O2 sensor and from what Ive read in the forums it would be the rear downstream 02 sensor. So my question is, should it be as simple as replacing that 02 sensor and my CEL should be gone?

Thanks guys!

 

If it is the second o2 sensor then is could also mean that the cat is bad, if you have a catless midpipe this is normal. The second one is not all that important, it just monitors the cat to see if it is working properly.

 

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