o2 problem, ses lights on and 4 sensor later

[lestat0669]

hi everyone Im going to make this as quick as possible and detail. Late out here and have to be up in a 3 hours. Few months ago my ses light turn on, check it with scan tool and code p0134 replace sensor, worked for a few weeks and light came up again same code got sensor replace work for a few days and the same thing got the sensor replace for the third time and it didnt last a day. auto part store refused to exchange the third sensor, they said it might be the harness. I read somewhere where a guy had a similar problem and they recommend to him to swap the sensors. Which I did and fortunately the other sensor worked on that bank. By the way I'm referring to the downstream sensors and if thats not the code, not to confused anyone its probably my mistake and its late for me. Well the ses light has been on for a while and my inspection is coming up in a few weeks and I need it gone. I tried everything I can imagine. I even took the liberty to buy another sensor (4th 0ne) different brand. Previous sensor where Bosches and last one a Walker. That didnt do any good either. Still ses light is on and no where to go from here. And yes I swap the sensor from bank to bank and the other sensor works fine. I have left it for days and no problem, so I assume its not a harness problem. What do you guys think????? Extremely puzzle on this one. I have a 98 tahoe LT. Any help will be very appreciate. Thanks for your time and patience........good night guys

 

[SunlitComet]

Now that you are awake check you code again because yes it is a defferent code. p0134 refers to left cylinderhead upstream sensor. Specifically the heater circuit. Also check for an exhaust leak typically within 30.5 cm (12 in.) up-stream of the HO2S.

 

[lestat0669]

I apologize if I confuse anyone with the wrong code, its actually p0140. The issue is with the downstream sensor, either bank when replacing it with a new sensor. I use the old one and it gives me a reading(fluctuating) in either bank but when replace with a new one it doesnt work in either bank. I hope I made it clear this time, not as sleepy as last night. Thanks guys

 

[SunlitComet]

http://www.sunlitcomet.com/pdf/automotive/tahoe/98-99/DTC P0140 HO2S.pdf

If the vehicle side test correctly swith to an Ac delco part

 

[lestat0669]

thanks sunlitcomet for your advice , I'll take that into consideration and thank you for the link. I'll try to make some sense of it. Why dont they right these instruction in plain english. More like o2 sensor for dummies.. Thanks again

 

[SunlitComet]

If I could I would be rich. But what I gave you is factory info which to me is kinda on the dummy side for me. I personally prefer more technical to make me happy. It was intended for high tech minds. You can try a haynes or chilton manual(for dummies?) but all they say is to refer to an experienced person. It maybe confusing but is precise and systematic approach to the problem from an engineering point of view. I can never get enough of it.