99 Chevy Silverado, 5.3, z71. Trouble codes p0138 and p0141. Itis thesame 02 Sensor, Bank 1 Sensor 2. I replaced 02 Sensor behind cat on driver side. The codes kicked back. Whats should I do? I really appreciate any help. Thanks.
Bryan

 

mine threw that code as well, i took them out and cleaned them with carb cleaner. You have to let them completly dry before using the truck. I went for two days. It worked great and the codes were gone.

 

Thanks popo. I'll have to give that a shot. This is just one of those petty problems that is really starting to bother me. Did you take out all 4 o2 sensors and clean them? I am guessing that isn't a bad idea. I was also mistaken. The old o2 sensor was giving me problem codes P0138 and P0141. I replaced that sensor and withina few minutes of driving with the new sensor, it kicked a P0140 Sensor CKT No Activity at me.

I am planning on taking out the new o2 sensor and returning it. It cost me $70. Then I'll try the cleaning idea.
Any other suggestions? Thanks.

 

Could that have been a bad newo2 sensor? It was a Standard bought from Bumper to Bumper.The guy there explained them to me as up stream anddown stream sensors. Thesensor kicking the codes is Bank 1Sensor 2, that is downstream, correct? I am pretty sure all the o2 sensors are original. I had a bat cat last year and replaced it, but I've had probs with this o2 sensor(Bank 1 sensor 2)ever since. But get this, my MPG has been good. Highway:18-20, city: 15-17. Part of me doesn't want to screw with it. But I want everything running right, it seems to be idling rougher than normal. Help!?!?!?
Bryan

 

The sensor will make it idle a bit rough. The Bank 1 Sensor 2 is the downstream on the drivers side. Did you get an OEM or did you get a universal? I have used the universal's before and they have worked ok but they were a pain to install due to the wiring connection. Make sure that you get the wiring right.

 

the code could also be stuck in your ECU which means you need to have it cleared out, in mine i was told disconect the battery terminals and hold them together for 10 secounds

 

I just unhook the batt overnight.

 

I cleaned all the sensors and also un plugged them from theharnesses. Check the wire connections as well then reinstall