How to fix Codes P0053 and P0135

[onecrazyfoo4u]

So my 2005 Sierra with the 5.3l keeps putting up these two codes, even after I clear them. It appears like it's a bad O2 sensor right? Which O2 sensor do I need to change out? Or is there something else wrong that you can tell from these 2 codes?

 

I did just change the spark plugs, but that was a few weeks ago before the codes started to post. I used the correct plugs, 41-110 Iridium. Thanks for the help!

[txab]

Driver's side, pre cat

 

Google the codes and see the various reason they may set and check those out before changing sensor

 

 

 

What causes the P0053 code?

• Faulty HO2 sensor
• Damaged or disconnected electrical connector at the oxygen sensor
• Faulty or shorted wiring in the oxygen sensor circuit
• Blown fuse for the HO2S sensor
• Low or excessive fuel pressure
• Vacuum leak on the engine
• Excessive exhaust leaks
• Faulty ECU (Engine Control Unit), in rare cases

[onecrazyfoo4u]

Just thought I would update that I replaced both pre-cat O2 sensors last week (with Denso's, ~$25 on rockauto). Instantly noticed about 1.5mpg increase and a much smoother idle. So these things will pay for themselves in a couple months. Well worth it.

 

Mine were probably original at 150k miles. Replace your O2 sensors people!