Upstream Downstream O2 Sensors Chevy Silverado GMC Sierra 6.0L

If your Sierra or Silverado isn’t running right, one of the leading culprits can be the oxygen sensor. The O2 sensors are responsible for reading your air fuel mixture to determine if your Chevy or GMC is running rich or lean. When you want to test your Silverado O2 sensor, use this guide here.

Vehicle Compatibility

Chevrolet

• Chevrolet Silverado 1500 → 2003–2006 6.0L V8
• Chevrolet Silverado 2500HD → 2003–2006 6.0L V8
• Chevrolet Silverado 3500HD → 2003–2006 6.0L V8
• Chevrolet Suburban → 2003–2006 6.0L V8

GMC

• GMC Sierra → 2003–2006 6.0L V8
• GMC Yukon XL → 2003–2006 6.0L V8

Cadillac

• Cadillac Escalade → 2003–2006 6.0L V8

Hummer

• Hummer H2 → 2003–2006 6.0L V8

【Comprehensive Compatibility】 This 4PCS Oxygen Sensor set includes two upstream (234-4669) and two downstream (234-4407) O2 Sensors, designed for 2003-2006 Chevy Suburban, Silverado 1500/2500/3500 HD, GMC Sierra, Yukon XL, Cadillac Escalade, and Hummer H2 with 6.0L V8 engines. Be sure that an excellent fit in your vehicle’s needs.

What’s Included

Upstream Sensors (Pre-Cat)

• Part #: 234-4669
• Monitor air/fuel ratio entering catalytic converters

Downstream Sensors (Post-Cat)

• Part #: 234-4407
• Monitor catalytic converter efficiency

【Direct Replacement Parts】 Engineered as direct replacements for OEM part numbers 234-4669 and 234-4407, these O2 Sensors are easy to install. Before purchasing, please verify your vehicle’s year, make, model, and compatibility to make sure proper fitment.
【Easy Installation】 Designed to OEM specifications, it’s the ideal replacement for the original sensor with a plug-and-play design that requires no modifications and may also be installed in only some minutes.

Common Symptoms of Bad O2 Sensors

Failing oxygen sensors can cause:

• Poor fuel economy
• Rough idle
• Check engine lights
• Sluggish acceleration
• Failed emissions tests
• Rich or lean running conditions

Basically, the ECU starts making bad decisions constantly.

4PCS O2 Sensor Kit Chevy Silverado Sierra Escalade H2 6.0L 2003-2006

Performance Benefits

Replacing all four sensors restores:

• Proper fuel trims
• Better fuel economy
• Smoother engine operation
• Correct emissions monitoring
• Improved throttle response

Your 6.0L finally stops wasting fuel unnecessarily.

【High Quality】 Made out of high-quality materials, our O2 Sensor has a long lifespan, providing your vehicle with long-term stability and excellent performance.
【Buy with Confidence】 Up to date Oxygen Sensor, professionally tested by professional before shipping. We offer a one-year unlimited-mileage guarantee on our meticulously crafted Oxygen Sensor, ensuring you’ll hit the road with peace of mind.

Installation Benefits

• Plug-and-play OEM-style connectors
• Direct-fit replacement
• No modifications required
• Fast installation process

(As long as the old sensors aren’t welded into the exhaust by 20 years of rust.)

Final Take

No horsepower gains.

But smoother operation, improved MPG, and fewer check engine lights make this one of the smartest maintenance upgrades for older GM trucks and SUVs.