P0141 & P0161 at same time

[DenisMcG]

My 98 Z71 with 5.7l is throwing both the 141 and 161 codes (O2 sensor #2) for both left and right rears. What are the chances that they would both go bad at the same time? The truck has 142,000 miles but runs great. It shows no signs of running rich, and gets around 17 mpg. Also, are there any problems with using aftermarket sensors, or should I just stick with the GM part.

 

Thanks,

 

Denis

[GM-Tech]

What are the chances that they would both go bad at the same time? 

 

Probably pretty slim. Keep in mind they share some of the same circuits (power, ground) and those DTC's are for heater performance, which sounds like there might be a loss of power to the sensors.

 

I believe the fuse that supplies them is ENG 1, though if that was blown, it should affect other things. Still worth a look.

[DenisMcG]

Thanks for the info. I had the system reset and after two days the light came back on. This time it is only P0141. I don't know if its just a matter of time till the P0161 shows up, or if it is just the left rear sensor. Would anyone have access to the schematic of the 02 sensor system, possibly in .pdf that could be emailed.

 

Thanks,

 

Denis

[Mr. Smith]

Thanks for the info.  I had the system reset and after two days the light came back on.  This time it is only P0141.  I don't know if its just a matter of time till the P0161 shows up, or if it is just the left rear sensor.  Would anyone have access to the schematic of the 02 sensor system, possibly in .pdf that could be emailed.

 

Thanks,

 

Denis

 

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I had both go on my 97. I change one and the other side came back. I too thought it was odd both came on. they had 98K when they took a dump.