[mostsleek]

I have 2 codes PO135 and the other code is for the bank 2 sensor 2 (I can not recall the code). PO135 is for bank 1 sensor 1. The PO135 just started yesterday, the other has been on for about 2 months. My question is would it be wise to replace all 4 O2 sensors, bank 1 and 2 and sensors 1 and 2, or is this one of those if it ain't broke don't fix it kind of things? I know that this is a very talked about topic, and I did a search and filtered through the first couple of pages and could not find anything about replacing all 4 at once.

 

[chinaloy]

I replaced the front two a few months ago. No new codes since.

 

[low c1500]

Buy two new sensors, and put them in the front of each back. Then take the one good front one and put it in place of the bad rear one. The front sensors control fueling, and the rear sensors only monitor the health off the cat.

 

[mostsleek]

Buy two new sensors, and put them in the front of each back. Then take the one good front one and put it in place of the bad rear one. The front sensors control fueling, and the rear sensors only monitor the health off the cat.

I knew that the rear sensors just checked the cat thats why I was in no hurry to fix it. But since the front control the fuel mix I will want to do that sooner. I will proabley do as you said, now I just have to find time...sigh .