O2 Sensor Problems

[cheyenne402]

Help!

I have this constant Trouble cose for my O2 sensor. Let me start from the beginning--. I took my truck in to the shop to get the exhaust fixed. The flnge around the exhaust was cracked where it meets the manifold. (Also had 3 broken manifold bolts on driver's side, 1 on passenger's side) Anyhow, they welded the cracks, truck back to being quiet.

Now the problem, ever since the truck got fixed, the "service engine soon" light keeps tripping. Code was P0137. Took truck back. Reset computer. Tripped again after driving. Took truck back again, they thought maybe bad connection on downstream O2 sensor. Reset again. Tripped again after driving.

Went out and bought my own code reader. Code still P0137. Reset multiple times, still same code tripping. So, I went and put new downstream O2 sensor on driver side. That didn't work. Still tripps the P0137 code. Now I am getting code P1133 also. This is from the upstream sensor on driver side, I believe.

Anyone have similiar problems or have any ideas for me? Any help is greatly appreciated. Thank you in advance.

[cheyenne402]

anyone?

[kszygc]

I got this in reply to my ? about them.

Quote:
Originally Posted by kszygc
Once a year or so I have to replace the downstream O2 sensors on a 99 Silverado. By that I mean the 2 sensors after the converter not the two before. It has the 5.3 w/ auto trans, auto 4x4. The previous owner cut the y-pipe and installed 2.25 inch pipe all the way to the rear without mufflers at all. I bolted on a pair of 4 inch supertrapps at the back end to cut down on my hearing loss, it's bad enough as it is. It has a K&N fitercharger kit and unknown brand of shorty headers. The computer is still stock though. I will get the DTC for low volts and no volts so I pull the sensor and it is in pieces internally. They aren't terribly expensive, I just get tired of replacing them. Anybody have any ideas or experience?

So I'm guessing you have 2 pipes one on each side, from the maniflod to the rear. Correct? If it is then I would put the 2 new downstreams in, and feel how much vibration is around them, if there is alot that could explain the internal pieces being broke. To fix that you could tac a hanger close to each pipe leaveing room to R&R the o2s if they go bad in the future. If possible use those hangers that have rubber straps on them to allow movement.

From what I researched for your codes, I'm not sure, are the sensors broken up internally? It sounds like the sensors is not switching over. It could be a bad sensor, even if it's not broken up, and it's just not responding. that would be my first guess. On the other hand, I've been also told that a bad burn in the combustion chamber can cause issues as well. Several other options come to mind but I doubt that two downstreams sensors are bad. Possibly the one you changed was bad from the factory. Can you swap from left to right on the downstream side? the upstream sensor could have been damaged by heat, vibration, or welding gases or slag. Once again, maybe clear them and swap the upstream sensors after proving the downstream ones. good luck

[cheyenne402]

Well, I changed the front sensor on the same side Friday. So far, no codes have tripped. We'll see?

As for switching downstreams, no, they aren't interchangeable.

Thanks for the help, I didn't think about the combustion issue. Hopefully it's not that.

[hvychve]

bank 1 sensor 2, is the sensor on the same side as cylinder #1 but behind the catalytic conver, bank 1 sensor 1 is going to be on the same side as cylinder one in front of the cat. with this known, now you need a meter that can messure voltage from .2 volts to .9 volts, at the signal wire of the o2, this is the wire that goes back to pcm to indicate what the oxygen content is of the exhaust, on the pre o2s, they better be fluctuation between .2 and .9 of a volt of a trouble code will set, I like to monitor freeze frame data before I clear the codes, this is info of when the code set and at what criteria of certain other inputs and data, but you have whats called a hard code, it is cleared and comes right back,I went to look up info for you on my all data , but came up empty handed , you gave no year or body style and engine size, po137 is switch rate issues, another words the computer didnt see the o2 switching , either you have wires pinched , or open from o2 to pcm (computer,) I think I remember reading you had already changed o2's , so I would guess you have eliminated that already, the other code you have is the same code, it just specifies vehicle specific with the p1133, the one instead of the 0 indicates vehicle specific, its the same as your first code, from what I can see you have bank 1 sensor 2 issues, I would find the correct schematic, (first by knowing what your working with) and pin the signal wire and see if its actually swithing voltage, and can it be foreced rich and lean, and does it show a change, lean being .2volts and rich being .9 volts,
This o2 also has whats called a heater, it has two wires, one is 12volts and another is a ground, you can check to see if you have both with a volt meter, you can also verify if the heater is shorted by checking continuity across the o2 itself to verify its not shorted. if o2 is switching at o2 , I would than want to see it either on a scan tool data parameter or back pin it at the pcm with a lab scope or volt meter , I hope I havent confused you, but on a post o2, (which is an o2 that is behind the cat), the computer is not looking for a switch rate, it wants to see a steady voltage of about .45 volts, this would indicate cat is working , if its switching , the cat is no good, the only reason for the o2 sensors behind the cat, is to monitor cat efficiency, and the 02 sensors upstream of the cats are for fuel control and trim correction.......good luck