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Discussion Starter · #1 ·
I have a 2004 Yukon 5.3L gas. I am getting a P0141 code. I have replaced the sensor with a new bosch unit but still getting the code. The old sensor that I removed was a Denso.
Are there any known issues with the bosch sensors?
Is there a fuse for the O2 heater circuit?
Can anyone tell me the proper way to test the 4 wire harness with a multi-meter to see if I am getting proper voltage for the heater circuit?
Thanks,
Brian
 

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JUGS Racing
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Check the voltage when in closed loop.

The oxygen sensor is on a 1 volt reference. So its 0-1 volt and target voltage should be around .5 volts.
 

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Discussion Starter · #3 ·
it reads proper voltage and seems to be working fine once it gets up to temp according to my scanner(.48-.67v), but I keep getting the O2 heater circuit malfunction code.
Haven't found any fuses or relays that are bad. I am guessing that the heater circuit would just be 12v when the ignition is in the run position. But not sure where to measure that.
Thanks for the reply. Still scratching my head.
 

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Discussion Starter · #5 ·
P0141 bank 1 sensor 2 is what my reader says. And according to my book that should be driver side post CAT. I had planned swapping it with the sensor on the passenger side to see if the code follows the sensor. But I got busy this weekend and didn't get a chance to do it.
 

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Discussion Starter · #6 ·
Ok so I finally got around to swapping the pass/driver O2 sensors to see if the code followed the sensor. Or if the code stayed in the same location indicating a truck wiring issue.
Swapped sensor and no code problem seems to be fixed. It was throwing the code within a few minutes of starting the truck but got almost 50mi in and no code so I have no idea what the hell caused the problem.
 

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Discussion Starter · #8 ·
Code stayed in the same position and did not follow the sensor. So it looks like I have some sort of wiring, fuse, or ground issue. Any help on where to start trouble shooting this?
 

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I've always heard rear o2 sensors exist only to make sure the cats are working correctly and they don't affect any engine management fuel trims or anything at all, they just turn on the light.

Assuming I heard correct and you don't live in a state that does inspections, and you have a code reader to see if anything new comes up and don't mind the light...well...buy some beer with that money or something.
 
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