2001 Yukon removing O2 sensor upstream Bank 1

[rockola1971]

Thanks for the reply. I used denso that I bought on amazon for about 24.00

MASSHOE4 is right. The upstream sensors are the only O2 sensors on your vehicle that are used as a input to the PCM for determining how much fuel to add or subtract from the fuel to air muixture. The downstreams only job in life are to tell you that your catalytic converters are no longer operating to spec and need replaced. That is why the downstreams are located after the cats and upstreams are located before the cats in the exhaust system.

 

[Ella ramaley]

I replaced both upstream with denso O2 sensors. I thought the codes went away. Went on a camping trip pulling a less than 2000 lb. Camper. Gas Milage was around 12mpg. ( less than I normally get) when I got home , smelled gas again on the outside of vehicle. No check or service engine light. But checked codes and both p1133 and p1153 were present. Previously didn’t have the p1133. Wonder what to do now. I erased the codes.

 

[rockola1971]

P1133 Chevy (Code Meaning, Causes and Fixes) – Chevy Guide

chevyguide.com

Below is a list of common causes for your Chevy P1133 code:

• Faulty O2 Sensor: The Lambda sensor may have failed, which would cause this trouble code.
• Faulty PCM: The PCM may have failed or have a software malfunction, causing the code to be stored.
• Leaky or Clogged Catalytic Converter: If the catalytic converter isn’t working properly, it could cause this trouble code to be stored.
• Open Circuit in Heater Element: If there is an open circuit in the oxygen sensor’s heater element, this trouble code will be stored.
• Clogged Fuel Injectors: A clogged injector could cause a lean condition and trigger this trouble code