O2 Oxygen Sensor Upstream Downstream for Toyota Tundra (2003-2004) 4.7L
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Direct-Fit Oxygen Sensor Kit for 2003-2004 Toyota Tundra (UCK30 / UCK40)
What it Does: The 4-piece O2 Oxygen Sensor Kit replaces degraded factory upstream and downstream sensors on the 2003-2004 Toyota Tundra to restore precise air-fuel ratio management and eliminate check engine lights.
The Stock Toyota Tundra Sensor Degradation
Factory zirconia elements on the first-generation UCK30 / UCK40 exhaust system suffer from thermal fatigue, silica contamination, and carbon fouling after extended heat cycles. Over time, internal heater circuit resistance rises, causing sluggish voltage switching between stoichiometric rich and lean thresholds. This delayed signal loop forces the ECU to dump excess fuel, resulting in unburnt hydrocarbons, catalytic converter deterioration, reduced MPG, and recurring P0135/P0155 trouble codes.
The Engineering Solution
Engineered to exact OEM operational tolerances for the 2UZ-FE engine, these direct-fit sensors utilize heavy-duty planar ceramic sensing cores shielded by dual laser-welded stainless steel protective sleeves. High-temp internal heater circuits achieve rapid operating light-off to enter closed-loop ECU fuel control immediately, safeguarding catalytic bed efficiency and maximizing combustion stability under heavy trail or towing loads.
What's Included
- 2X 234-4169 Upstream Oxygen Sensors
- 2X 234-4161 Downstream Oxygen Sensors
Technical Specifications
| Fitment | 2003-2004 Toyota Tundra |
|---|---|
| Engine / Chassis | 2UZ-FE / UCK30 / UCK40 |
| Stock Output | 245 hp / 315 lb-ft |
| Replaces OEM Part # | S4-4161, 234-4169, 2344161, 2344169, 13441, 2131443, 5S4203, 894650C140, 894650C150, 8946534080, 8946534110, 8946534120, 8946534130, 13051, 13095, 2131434, 2131435, 2131495, 24554, 8946509100, 8946509130, 8946509150, 8946509380, 8946539895 |
Compatibility
- 2003-2004 Toyota Tundra 4.7L V8 (Base, SR5, Limited; 2WD & 4WD)
Frequently Asked Questions & Fitment Warnings
Does this fit the UCK30 / UCK40 Tundra?
Yes, this is a direct fit for the 2003-2004 Toyota Tundra equipped with the 2UZ-FE 4.7L V8 engine; verify your engine displacement as this kit does not fit 3.4L V6 models.
Are wire splicing or harness modifications required for installation?
No, these sensors feature factory-matched harnesses and locking connectors for direct plug-and-play installation without wire splicing.
The Toyota Caliber
Built to handle harsh underbody heat and continuous payload duty cycles, these direct-fit sensors maintain steady fuel trim feedback to keep your Tundra running strong across high-mileage highway miles and heavy hauling conditions.
Fitment
Fitment
Warranty
Warranty
