O2 Oxygen Sensor Upstream Downstream for Chevrolet Tahoe (2003-2005) 5.3L

Direct-Fit Upstream & Downstream O2 Oxygen Sensor Kit for 2003-2005 Chevrolet Tahoe (GMT800)

What it Does: This four-piece upstream and downstream oxygen sensor kit measures pre- and post-catalyst exhaust oxygen content on 2003-2005 GMT800 Chevrolet Tahoe LM7 / L59 5.3L V8 models for precise PCM fuel trim control.

The Stock Chevrolet Tahoe Oxygen Sensor Failure

On the GMT800 platform powered by the LM7 / L59 5.3L V8, factory narrowband sensors endure severe thermal cycling and heater circuit fatigue. Carbon soot and moisture contamination foul the platinum electrodes and crack the ceramic zirconia element. As switching speed slows and heater resistance drifts, the PCM loses closed-loop fuel control, triggering P0135, P0155, and P0171/P0174 codes.

Common Symptoms of a Failing OEM Oxygen Sensor

• Check Engine Light / DTCs: Triggers P0135, P0141, P0155, or false P0420/P0430 catalyst codes from sluggish sensor voltage.
• Delayed Closed-Loop Operation: Cold starts run overly rich, fouling spark plugs and causing raw fuel odor.
• Poor Economy & Rough Idle: Skewed fuel trims reduce towing MPG and fail OBD-II readiness monitors.

The Direct-Fit Zirconia O2 Sensor Solution

This matched four-sensor kit replaces both upstream and downstream positions simultaneously to restore balanced closed-loop fueling on the LM7 / L59 5.3L V8. Each unit uses a fast-light-off internal heater and laser-welded stainless housing that resists thermal shock and road corrosion. OEM-length harnesses and Weather Pack connectors match 12584925, 234-4342, and 234-4668 specs for plug-and-play installation without splicing.

What's Included

• 2x Upstream Oxygen Sensors
• 2x Downstream Oxygen Sensors

Technical Specifications

Compatibility

• 2003-2005 Chevrolet Tahoe 5.3L V8 (2 Upstream & 2 Downstream)
• Excludes 4.8L V8 models, 2000-2002 Tahoe, and 2006-2007 Tahoe

Frequently Asked Questions & Fitment Warnings

Does this fit the GMT800 Tahoe?

Yes. This is a direct fit for the 2003-2005 Chevrolet Tahoe equipped with the LM7 / L59 5.3L V8 engine. Excludes the 4.8L V8 engine as well as 2000-2002 and 2006-2007 model years.

Will this clear P0135/P0155 and P0420/P0430 codes?

Yes, if faulty sensors are the cause. Restoring upstream switching and downstream monitoring resolves P0135/P0155 heater faults; persistent P0420/P0430 codes indicate catalytic converter failure.

Are these plug-and-play, and what installation prep is needed?

Yes. Direct-fit connectors match 15156, 15564, and 12584925; soak rusted bungs with penetrant, keep anti-seize off the sensor tip, and torque to spec.

The Chevrolet Heavy-Duty Standard

Engineered for sustained exhaust heat under heavy towing loads, these matched sensors keep your GMT800 Tahoe in crisp closed-loop fuel trim. Restore factory throttle consistency and emissions readiness across all four banks.