Got a P0136 a while ago (checked at the shop using an OBDII scanner), had it reset, now it came back (as 0707, checked myself)

Is it time to replace rear O2 sensor or is there anything else that could be wrong? Car runs fine otherwise, no other codes except for 0304 - KS. KS is bad for sure, fails resistance test.

Question, should i replace both KS and rear O2, or replace KS, reset, and see if O2 code comes back again?

Car has 117K miles and runs fine, fuel economy is good, altho i do drive very gently these days.

Thanks in advance.

 

Def replace the KS first. With mine, I was getting both codes, and then one day I got a new code for a front o2 sensor.

Replace the KS, reset ECU and 20 miles later, the two o2 codes were back on. Replace the front O2 sensors, and I just got a new rear one in the mail, waiting to install it.

 

Check the resistance on the O2 sensor to make sure it was the culprit. It may very well be a begining of a clogged or failing cat.

 

Naa, i doubt it's the cat. The car passed emission very recently, and none of the values were close to the limits. Besides, isn't there a code for the cat? Or am i missing something here....

 

there is no code for the cat, only the rear o2 sensor.

 

Yeppers, and that O2 sensor monitors the Cat.

 

My bad...ok I guess I'll hold off on swapping the O2 out for now, will swap KS and reset ECU see if the code comes back, and will check resistance on O2 sensor.

Thanks for your advice guys.