Catalytic converter Temperature Sensor

[Larry Huffstutler]

My 2015 Silverado 1500 5.3l has a converter on the passenger side that sits at 432 F and does not increase while running. The driver side cat reaches well over 1000 to 1500F. I got the dreaded P0430 code and it looks like most say to replace the converter. I did replace the downstream O2 sensor thinking that is where the control module was getting the temperature but it made no difference. The sensors on both banks read about the same O2 levels with the front sensors a little higher than the backs. Any ideas other than a wiring problem?

Thanks

[swathdiver]

1 hour ago, Larry Huffstutler said:

My 2015 Silverado 1500 5.3l has a converter on the passenger side that sits at 432 F and does not increase while running. The driver side cat reaches well over 1000 to 1500F. I got the dreaded P0430 code and it looks like most say to replace the converter. I did replace the downstream O2 sensor thinking that is where the control module was getting the temperature but it made no difference. The sensors on both banks read about the same O2 levels with the front sensors a little higher than the backs. Any ideas other than a wiring problem?

Thanks

No wiring problem, the computer is telling you that the catalytic converter is bad.  So guess what, the cat is bad.  Replace the cat.  BTDT.  Cheap Chicom cats last less than a year, when mine went, they were replaced with Magnaflow's hi-flow cats and y-pipe.

[Larry Huffstutler]

Thanks for the response. Cat is what I figured but would a bad cat cause the temperature not to change? It seems that there is some flow through the converter or I would have some drivability problems. Any flow at all and the temperature ought to change some.  

I wouldn't think I would have good O2 readings if the converter was really bad. Where does the temperature reading for the cat actually come from?

[CamGTP]

There isn't an actual sensor at all.

 

The o2 sensors are before the cat and after the cat, there is no sensor in the middle of the catalytic converter itself. If you took a temp gun to the outside of the converter you'd only see around 350-500 degrees depending on how hard you just drove the vehicle and where you placed the temp gun. We do not know the actual temp in the middle of the converter itself, it's more of a calculated number than anything.

 

 

 

The pre-cat o2 sensors will always swing lean and rich of 450-500mv on a scan tool. Typically ~100-900mv swings in a somewhat steady motion. The post cat o2 sensors should level off around 500-700mv on a scan tool with very little movement if the cat itself is doing it's job correctly. If the post cat o2 sensor starts to follow the pre-cat o2 sensor in a lean/rich swing then the cat is no longer doing it's job and will trip a check engine light.