1999 Chevy Tahoe has check engine light on. Test shows P-0161 bank 2 sensor 2 problem. Where is this? Is it easy to fix? Are the replacements expensive?

 

This is the oxygen sensor in the exhaust. Bank 2 is the right side of the engine and sensor 2 is the downstream sensor. The second one. They should cost under $50.00 depending on the brand you buy. Not that hard to change. Sometimes they get stuck and a bit hard to remove. Make sure to put some anti-sieze compound on the new one. Some of the sensors come with the compound already on the threads.

 

So this is on the drivers side between the catalytic converter & muffler, right?

 

Bank 2 is on the passenger side.

 

I have had this same issue on my 1997 Tahoe. To confirm that the O2 sensor was bad, I moved sensor (Bk1/Sn2) to (Bk2/Sn2) and vice versa, moved (Bk2/Sn2) to (Bk1/Sn2). Ran the vehicle until it set a code. The code moved to the other bank, confirming that the sensor was the issue. When I had the old sensors out, I sprayed them with injector/carb cleaner before re-installing them into their switched location. Next, I have less than ¼ of tank of fuel; I added two bottles of Chevon Techron injector cleaner to the fuel tank. Next, cleared the codes, and then ran it until it set a code. Next day it had confirmed it was the sensor by moving. I ordered all new O2 sensors, since I had not changed them since got this vehicle. I cleared the codes after confirming code moved and waited until parts came in. A week later, parts came in; I pulled the old sensors out, and installed the new one. After installing the new sensors, I went to clear the codes, and found that no codes had set since the switching of the banks on sensor 2. This made me realize that the injector cleaner and running it for week had resolved the problem and that I didn’t need to change any of the sensors. I should have checked the codes before proceeding to replace the sensors.

 

I put 1 bottle that treats up to 25 gallons in a tank full of gas. It seems to of worked! YAY! Thank you a thousand times over!

 

My post was to be an FYI, I went through trouble shooting to see if the problem would move to the other bank, and it did. Logic confirmed that the PCM had detected that the sensor was not giving a good signal to the PCM. If the code had stayed on the original bank, This would tell me that I had a wiring issue with that sensor. By cleaning them with carb cleaner and then running the strong injector solution and running it for a week, it burned away any of the gunk on the sensor(s), enabling the PCM to be able to sense the Exhaust stream. Some times I will run a bottle of this cleaner just as a preventative measure. Running injector cleaner has worked for other emission codes errors, like misfires. This was some what of a shotgun approach, I performed more then one test at a time to reduce the time to find a solution to the problem. I takes time for the PCM to detect and set a error code.

 

Thank you anyway for your response. It still hasn't come back on.