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Discussion Starter · #1 ·
The check engine light on my 05 CTS-V just came on with the following codes, P0155 and P0059. These are both of the front 02 sensors. Is it normal for both sensors to go out at the same time or could something else be causing them to fail? I'd hate to replace them to have them fail again.

Also does anyone know the part numbers for the parts?
 

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04' Blown CTS-V 554rwhp 497rwtq
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The check engine light on my 05 CTS-V just came on with the following codes, P0155 and P0059. These are both of the front 02 sensors. Is it normal for both sensors to go out at the same time or could something else be causing them to fail? I'd hate to replace them to have them fail again.

Also does anyone know the part numbers for the parts?
No those are both codes for the front O2's on bank 2 (passenger side). My guess is you just need to replace it and for that head on over to rockauto.com.

P0059 - HO2S Heater Resistance Bank 2 Sensor 1
P0155 - HO2S Heater Performance Bank 2 Sensor 1
 

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2006 CTS-V
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Hi everyone, I am relatively new to the forum and have owned my '06 V for a little over a year. Question about the O2 sensor... have any of you changed to improve performance due to age? I have 69,000 miles on mine, and have heard these sensors age and slow. Any recommendations on changing (I have no codes) and which brand to use?
Thanks!
 

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04' Blown CTS-V 554rwhp 497rwtq
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And stick with OEM Bosch replacements.
 

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Discussion Starter · #7 ·
Just a follow up. I changed out the oxygen sensor and reset the code. But the code keeps coming back. The car seems to be driving fine and I haven't noticed a degradation in fuel economy.

Any ideas as to what else could be causing this or what else to try?
 

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'06 Z06, '05 CTS-V 453rwhp/434rwtq (sold)
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I lost the passenger side front o2 sensor at about 70,000 miles, got the check engine light and gas mileage dropped about 2 mpg. I replaced both bank 1 and 2 at the same time to keep everything fresh. I have heard that these sensors "slow" down over time, so it seemed like the right thing to do to replace them together.

If you did replace the correct sensor and still have the cel, check the wiring for any damage.
 

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04' Blown CTS-V 554rwhp 497rwtq
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Just a follow up. I changed out the oxygen sensor and reset the code. But the code keeps coming back. The car seems to be driving fine and I haven't noticed a degradation in fuel economy.

Any ideas as to what else could be causing this or what else to try?
And stick with OEM Bosch replacements.
Did you do this? The reason I said it was not because I own stock in Bosch but rather because people have had problems with non-OEM o2's.

If they are Bosch then my next step would be to monitor them switching while you idle and are up to temperature. To do this though you will need a scan tool. They should be switching from roughly 100mv to 900mv. If you see your bank 2 sensor (pass side) is static at like 450mv for instance then it needs replaced.
 
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I'm sorry to hear the codes came back, thecatalyst! If they persist and a DIY fix isn't found, I hope you'll consider going to a dealership for a diagnosis. However, I see that the community members are already replying with helpful feedback, and I'm hoping a resolution is found quickly.

Please don't hesitate to email me anytime at [email protected] for further assistance.

Katie
Cadillac Customer Service
 
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