O2 Oxygen Sensor Upstream Downstream for Lexus GS (2007-2008) 3.5L

Direct-Fit O2 Oxygen Sensor Kit for 2007-2008 Lexus GS (S190)

What it Does: This 4-piece oxygen sensor kit monitors upstream and downstream exhaust gas levels on the 2007-2008 Lexus GS (S190) 2GR-FSE 3.5L V6 to maintain accurate fuel trims and emissions compliance.

The Stock Lexus GS Sensor Failure

Through repeated heat cycles on the S190 chassis with the 2GR-FSE 3.5L V6, factory zirconia sensors suffer carbon fouling, silicone contamination, and internal heater burnout. Sluggish upstream air-fuel response skews Bank 1 and Bank 2 fuel trims, while fatigued downstream units trigger P0420/P0430 catalyst codes or P0135/P0155 heater faults. Replacing only one failed sensor leaves aged opposing-bank units lagging, causing uneven fueling.

Common Symptoms of a Failing OEM O2 Sensor

• Check Engine Light / DTCs: Triggers P0135, P0155, or P0420/P0430 from slow response or heater failure.
• Fuel Trim Imbalance: Causes rough idle and hesitation across Bank 1 and Bank 2.
• Emissions & Economy Loss: Increases fuel consumption, exhaust odor, and inspection failures.

The Direct-Fit 4-Piece Oxygen Sensor Solution

This matched 4-piece direct-fit kit replaces both upstream air-fuel ratio sensors and both downstream heated oxygen sensors simultaneously on the S190 Lexus GS. Built to OE interchange specs 234-9051 and 234-4521, each unit features corrosion-resistant stainless steel housings, heat-shielded harnesses, and factory-keyed connectors. Direct-thread bungs enable clean plug-and-play installation without cutting or splicing, restoring synchronized closed-loop lambda feedback across both exhaust banks.

What's Included

• 2 Upstream Air-Fuel Oxygen Sensors (234-9051)
• 2 Downstream Oxygen Sensors (234-4521)

Technical Specifications

Compatibility

• 2007-2008 Lexus GS 3.5L (GS 350) — S190 Chassis / 2GR-FSE V6 (4-Piece Upstream & Downstream Set)

Frequently Asked Questions & Fitment Warnings

Does this fit the S190 GS?

Yes. Fits 2007-2008 Lexus GS 2GR-FSE 3.5L V6 models. Excludes 2009-2015 models, IS 250 2.5L, IS 350 3.5L, and GS 450h.

Will this clear P0135, P0155, or P0420/P0430 codes?

Yes, if sensor-related. Matched 234-9051 and 234-4521 units resolve heater and switching faults; persistent P0420/P0430 codes require catalytic inspection.

Are wire splicing or adapters required?

No. Each sensor includes OE-length harnesses and keyed connectors for plug-and-play installation; keep anti-seize off sensor tips.

The Lexus Precision Standard

Built for CEL-free operation on the 2GR-FSE platform, this matched 4-piece sensor kit restores factory fuel control and throttle response.