02 Sensor help
 

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Ok so I am posting this for my fiance. Anyways she has a 01 V6 Camaro. She has had a check engine light on for a little while now. We went down to Auto zone and they pulled codes P0131 P0151 P0137
Code 131 says Input voltage from 02 sensor 1 in bank 1 is too low
151 says Input voltage from 02 Sensor 1 bank 2 is too low
137 Input voltage from 02 sensor 2 bank 1 is low

So I am guessing that sensor 1 and 2 are bad. Is this correct? How hard are these to change? Any help is apreciated. Thanks

RE: 02 Sensor help
 

You need a scan tool to look at the output of the O2 sesnsors and see if the voltage is constantly cyclyng above and below 0.5 Volt. If it is steady (either above or below 0.5 Volt) the sensor is bad. When the downstream sensor follows the activity of the upstream sensor, the cat is bad. I your case, a low reading in all 3 sensors would suggest a lean mixture. But you have to be sure that the sensors are working properly to begin with.

RE: 02 Sensor help
 

thats your two manifold o2's and your precat sensor. all 3 will be about 180 bucks from the parts store. its hard to say if theyre bad for sure without autotap or a similar program. you can buy sensor testers for cheap, and then remove and test them. or you could just go buy all 3 and replace. they simply screw out of the exhaust (theyll be rusted in tight though for sure) and have an electrical connection on the other end.