O2 Oxygen Sensor Upstream Downstream for GMC Sonoma (2000-2003) 2.2L

Direct-Fit Upstream & Downstream O2 Sensor Kit for 2000-2003 GMC Sonoma (GMT325)

What it Does: This upstream and downstream oxygen sensor kit monitors exhaust oxygen on the 2000-2003 GMC Sonoma GMT325 LN2 2.2L to regulate fuel trim and catalyst efficiency.

The Stock GMC Sonoma Oxygen Sensor Failure

Over repeated heat cycles on the GMT325 chassis, factory zirconia elements suffer carbon fouling and internal heater burnout. Exhaust heat soak along the LN2 2.2L I4 manifold degrades the upstream sensor response rate, slowing voltage switching between rich and lean states. Simultaneously, a lazy downstream sensor compromises catalyst monitoring, triggering P0135, P0141, and P0171 diagnostic trouble codes while skewing closed-loop fuel delivery.

Common Symptoms of a Failing OEM Oxygen Sensor

• Check Engine Light / Heater DTCs: Codes like P0134, P0135, or P0141 from failed sensor heaters or sluggish voltage.
• Rich Fuel Trim & Rough Idle: Skewed upstream feedback forces rich open-loop fueling and unstable idle.
• Poor MPG & Failed Emissions: Delayed O2 feedback cuts fuel economy and triggers false P0420 faults.

The Direct-Fit Matched O2 Sensor Solution

Replacing both sensors as a matched set restores synchronized pre- and post-catalyst feedback on the GMT325 exhaust. Each direct-fit unit uses a fast-light-off heated ceramic element inside corrosion-resistant stainless steel with factory weatherpack connectors. Precision protective shields resist thermal shock and fouling while maintaining OEM thread geometry. No splicing is needed, as both sensors thread directly into stock manifold and exhaust bungs for accurate ECM calibration.

What's Included

• 1 Upstream Oxygen Sensor
• 1 Downstream Oxygen Sensor

Technical Specifications

Compatibility

• 2000-2003 GMC Sonoma 2.2L (GMT325 / LN2 — 2-Sensor System)
• Chevrolet S-10 2000-2003 2.2L is offered separately; confirm engine before ordering.

Frequently Asked Questions & Fitment Warnings

Does this fit the GMT325 Sonoma?

Yes. Direct fit for the 2000-2003 GMC Sonoma with the LN2 2.2L engine. Excludes 4.3L V6 models; verify engine before ordering.

Will this clear P0135 and P0141 codes?

Yes, when caused by worn sensors. New upstream and downstream sensors restore heater resistance and voltage switching to resolve P0135 and P0141.

Are connectors plug-and-play without splicing?

Yes. Direct-fit OEM connectors and factory-length harnesses thread straight into stock GMT325 bungs.

The GMC Heavy-Duty Standard

Built for thermal durability under daily hauling on the GMT325 platform, this matched set maintains accurate closed-loop fueling and reliable emissions compliance.