O2 Oxygen Sensor Upstream Downstream for Chrysler 300 (2005-2010) 3.5L

Direct-Fit O2 Oxygen Sensor Kit for 2005-2010 Chrysler 300 (LX)

What it Does: This four-piece upstream and downstream O2 sensor kit monitors pre- and post-catalyst exhaust oxygen on the 2005-2010 Chrysler 300 LX (EGG 3.5L V6) to preserve closed-loop fuel trim accuracy.

The Stock Chrysler 300 Sensor Failure

Factory oxygen sensors on the LX equipped with the EGG 3.5L V6 endure extreme exhaust thermal cycling, moisture condensation, and carbon contamination over time. As the internal zirconia element degrades and the heater circuit builds resistance, voltage switching slows and starves the PCM of accurate bank-to-bank feedback. Replacing only one failed sensor leaves aged units on the opposite bank, causing fuel trim imbalances and repeat P0135 or P0155 heater faults.

Common Symptoms of a Failing OEM O2 Sensor

• Check Engine Light / DTCs: Slow switching or open heater circuits trigger P0131, P0135, P0155, or catalyst codes P0420/P0430.
• Fuel Trim Imbalance: Sluggish millivolt response forces rich open-loop fueling and triggers P0171/P0174 trim faults.
• Emissions & Idle Issues: Corrupted lambda data degrades catalytic efficiency, causing rough idle and failed emissions tests.

The Direct-Fit Heated Zirconia O2 Sensor Solution

This matched four-sensor set restores uniform upstream fuel metering and downstream catalyst monitoring across both exhaust banks simultaneously. Each unit features a fast-light-off heated zirconia sensing core inside a corrosion-resistant stainless shell with laser-welded shields to resist thermal shock. Pre-coated anti-seize threads and OEM-style locking connectors ensure plug-and-play installation without cutting or splicing, directly replacing interchange numbers 234-4030 and 234-4274.

What's Included

• 2 Upstream Oxygen Sensors
• 2 Downstream Oxygen Sensors

Technical Specifications

Compatibility

• 2005-2010 Chrysler 300 — 3.5L V6 (EGG / LX Chassis)

Frequently Asked Questions & Fitment Warnings

Does this fit the LX 300?

Yes. Direct fit for the 2005-2010 Chrysler 300 with the EGG 3.5L V6. Excludes 2.7L, 5.7L HEMI, and 6.1L SRT8 engines; confirm 3.5L fitment before ordering.

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

Yes, when sensor-related. Installing a matched set restores switching speed and heater resistance, resolving P0135/P0155 faults and false P0420/P0430 triggers from lazy rear sensors.

Is any wiring modification required?

No. All four sensors use direct-fit OEM connectors and pre-applied anti-seize; chase corroded bungs with an M18x1.5 tap before torquing.

The Chrysler Precision Standard

Restores factory PCM feedback on the LX chassis for accurate closed-loop fueling and CEL-free compliance on your EGG 3.5L V6.