5.3L Oxygen Sensor Issues

[Iggy913]

Greetings all,

 

I’ve got a 2013 Suburban with the 5.3L and about 90k Miles.

 

Recently it’s started throwing a code for the oxygen sensor, Bank 2 Sensor 1. I replaced the sensor on the passenger side upstream, all was good, the CEL went out during my initial drive after the repair was made.

 

About a month later the CEL came on again, this time indicating Bank 1 Sensor 1. I knew better just replacing one previously and should have done them both the first time. At any rate I go to remove the drivers side sensor only to discover it was cross threaded by the previous owner and secured with a TAC WELD!!! I ended up having to remove the entire Y Pipe to remove the sensor. About half the threads were ruined but I was able to run a tap into the bung and make new threads in the bottom half of the bung, allowing me to secure the new sensor in place.

 

Job done, I went to the local auto parts store and reset the code, life good again. The next day the CEL comes on again indicating Bank1 Sensor 1, delayed response, P015B I believe. I removed the one day old sensor and put a touch of copper seal RTV thinking, although I was able to make new threads in the bung that maybe it wasn’t sealing completely, causing an exhaust leak and poor oxygen reading?

 

Code reset and took the truck for an hour drive to confirm. The second day the code reappears for the second time. What am I missing? I find it hard to blame the sensor or the wiring due to the truck running for about an hour before the code is set, or am

I missing something? I’m using Denso oxygen sensors

 

any help would be greatly appreciated 

[Supreme Pizza]

Try swapping the sensors. See if the code follows the sensor. If not, you have a wiring issue or perhaps a ratio problem. 

[Iggy913]

I thought about swapping the sensors, if the code followed the sensor, then yes that would show me if the sensor was bad. My fear is if it does not follow the sensor that my problem is related to the bung itself being still slightly cross threaded and not making a solid seal. 

 

Maybe I’m missing something but if I had an issue with fuel delivery, like the fuel pump or injectors, wouldn’t that set the code for both left and right banks?

[Supreme Pizza]

The code would be set on the side that has the issue. Lets say you have one bad injector. That bank would throw a code. If you had a bad pressure regulator, it would throw codes for both banks. I would buy a $20 Amazon sensor and swap it. Cheap and easy to try. If it doesn't work, keep the sensor as a spare, or return it. 

 

As for the exhaust leak, you could try this: 

 

 

https://www.amazon.com/J-B-Weld-37901-Temperature-Resistant/dp/B01IBOBY74/ref=sr_1_2?ie=UTF8&qid=1532873544&sr=8-2&keywords=exhaust+sealer

 

[swathdiver]

On 7/28/2018 at 9:13 AM, Iggy913 said:

Bank1 Sensor 1, delayed response, P015B I believe.

That's not a GM code.  There are two similar, Insufficient Activity (P0134) and Slow Response (P0133).  There are several other codes that identify what could be wrong with a sensor as well.    

[Iggy913]

I’m not sure what you mean by P015B is not a GM Code? When I use a cheap scanner at Advance Auto Part Store that’s the code it displays.

 

When I google what that corresponds to I get “O2 Sensor Delayed Reaponse”  - Lean to Rich, Bank 1 Sensor 1.

 

I've tried to do my due diligence as I’m a competent DIY mechanic, replacing the offended sensor since that’s what was quoted as the most common cause. I then cleared the code using the same el-cheapo Advance Auto Scanner. In both previous cases the truck drives great with no light for about an hour, thinking I’m done I park the truck and smile. The next morning when my wife takes the truck for a 20 minute drive to work, she has texted me twice saying the light has returned.

 

The truck seems to idle smooth and have the same power and fuel mileage it’s always had so I’m not sure where to go?

 

I’m going to switch the two upstream exhaust sensors and see if that changes anything to rule out a sensor problem, I’m also going to use a little sealant on the drivers side sensor to hopefully remedy any exhaust leak around the sensor due to the previous owners crossthreading. Lastly I’m going to throw some fuel system cleaner in the tank to see if that changes anything, as others have mentioned success with this code and doing that.

 

any other ideas or recommendations?

[swathdiver]

25 minutes ago, Iggy913 said:

I’m not sure what you mean by P015B is not a GM Code?

Like I said, that is not a code used in the shop manual for your truck or any other GMT900.  The code is probably one of the two mentioned earlier.  You're doing the right and smart things by swapping sides (upstream and downstream are different on GMT900s) and then fixing that bung.  Chemicals can also cause a sensor to set off codes whether they be silicone from gaskets at the intake or the stuff used to seal the threads, they can cause a trouble code and or wreck an O2 sensor.  My memory fails me at the moment as to which chemicals, you'll have to look those up.