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Choosing the right Mitsubishi Eclipse oxygen sensor matters because a poor-fitting or slow-responding unit can cause drivability problems, higher emissions, and recurring check-engine alerts. You want a sensor that matches the vehicle's original fitment, gives accurate, fast readings, and survives common underhood stresses. This guide highlights seven shortlisted options that meet those priorities. We evaluated items for fit, wiring and connector match, response speed, and durability to help you pick the right replacement for your Eclipse. Read on to find the units that best balance fit and reliable signal performance.
Looking for other parts? See all Mitsubishi Eclipse parts & accessories.
Top Picks at a Glance
| Best Reviewed A top-rated pick with lots of positive feedback | Bosch 13407 Premium Fitment Oxygen Sensor |  |
| Most Popular A crowd favorite that many people choose with confidence | Bosch 15514 Premium Fit Oxygen Sensor |  |
| Best Quality Built to a higher standard if you want something more solid | Bosch 15578 Premium Fit Oxygen Sensor |  |
| Best Budget The cheapest option that still gets the job done reliably | Carock 2‑Piece Upstream and Downstream Oxygen Sensors for 2004–2012 Mitsubishi Eclipse / Galant 2.4L |  |
| Most Sold A high-volume bestseller chosen again and again | A-Premium Oxygen Sensor 4-PC Set for Mitsubishi Eclipse 2006-2012 (I4 2.4L) |  |
| Best Value for Money The sweet spot between price and what you get | Denso 234-4738 Oxygen Sensor |  |
| Best Overall The best all-around choice for most situations | Bosch 18074 Premium Fitment Oxygen Sensor |  |
1. Bosch 13407 Premium Fitment Oxygen Sensor
| Brand | Bosch |
|---|---|
| Material | Ceramic |
| Mounting Type | Flange Mount |
| Upper Temperature Rating | 250 Degrees Celsius |
| Manufacturer Part Number | 13407 |
This Bosch 13407 is a direct-fit oxygen sensor built as a factory-quality replacement for select Mitsubishi Eclipse models from the late 1990s. It is used to replace a faulty upstream or downstream O2 sensor so the engine control module can accurately manage fuel trim and emissions. Notable features include a fast-acting heater for rapid warm-up, a double laser-welded stainless steel body for corrosion resistance, and pre-coated threads and direct-fit connectors that simplify installation. In real-world use the fast heater helps the sensor reach operating temperature quickly, reducing the time the engine runs in open-loop after a cold start and helping with drivability and emissions. The welded stainless body and factory testing suggest good long-term durability compared with cheap generic sensors. Limitations are that this part fits specific Eclipse model years and sensor positions only, and the listing does not include vehicle-specific fitment confirmation beyond the general compatibility range, so buyers should verify position and engine fit before ordering.
Best for: Reliability-focused owners who prioritize a factory-quality replacement that aims to restore proper fuel control and emissions behavior on older Mitsubishi Eclipse vehicles.
Less Ideal for: Buyers seeking a universal or multi-year solution without checking engine and sensor position should look for parts explicitly listed for their exact vehicle and engine combination.
- Direct-fit connectors and pre-coated threads simplify bolt-in installation
- Fast-acting heater brings the sensor to operating temperature quickly for better cold-start performance
- Double laser-welded stainless steel body resists exhaust corrosion for longer service life
- 100% functional testing at the factory reduces risk of receiving a nonworking unit
- Compatibility limited to select 1996–1999 Mitsubishi Eclipse applications and specific sensor positions
- Fitment details rely on buyer verification rather than explicit, engine-specific confirmation in the listing
Verdict A reliable, factory-quality direct-fit sensor for select 1996–1999 Mitsubishi Eclipse models that prioritizes durability and fast warm-up but requires careful fitment verification.
2. Bosch 15514 Premium Fit Oxygen Sensor
| Brand | Bosch |
|---|---|
| Material | Ceramic |
| Mounting Type | Flange Mount |
| Output Type | Digital |
| Upper Temperature Rating | 1000 Degrees Celsius |
This Bosch 15514 is a direct-fit oxygen sensor intended to replace a failing upstream sensor on compatible Mitsubishi Eclipse models. It measures exhaust oxygen content and reports to the engine control unit so the ECU can adjust fuel mixture and maintain emissions performance. Notable features include a fast-acting heater that brings the sensor up to operating temperature quickly, a double laser-welded stainless steel body for corrosion resistance, and true direct-fit connectors with anti-seize on the threads to simplify installation. In practical use the sensor should clear oxygen-sensor related check-engine codes and restore smoother idle and more consistent fuel economy when the original sensor has aged. Installation is straightforward for a DIYer familiar with exhaust work, though access can be tight and an O2 sensor socket or removal tool makes the job much easier. This is a single-sensor solution so buyers should confirm the exact sensor position and engine fitment for their Eclipse before ordering, and note that electrical or exhaust-system damage unrelated to the sensor will not be fixed by replacement.
Best for: Convenience-driven buyers who want a factory-quality, direct-fit oxygen sensor that installs with minimal modifications and restores emissions-related operation on a Mitsubishi Eclipse.
Less Ideal for: Owners looking to diagnose unrelated engine or exhaust faults or those who need a universal or custom-length sensor for nonstandard installations should consider other options.
- Direct-fit connector and pre-coated threads simplify installation and reduce prep work
- Fast-acting heater shortens warm-up time so the sensor reaches operating temperature quickly
- Double laser-welded stainless steel body resists exhaust corrosion for longer service life
- 100% functional testing at the factory reduces the chance of receiving a defective unit
- Designed as a single replacement part so you must verify sensor position and engine compatibility for the Eclipse
- Access and removal can be difficult without an O2 sensor socket or lift
Verdict A reliable, ready-to-install direct-fit sensor that makes replacing a failed upstream oxygen sensor on a Mitsubishi Eclipse quick and hassle-free.
3. Bosch 15578 Premium Fit Oxygen Sensor
| Material | Stainless Steel |
|---|---|
| Measuring Range | 0% – 21% O2 |
| Output Type | electrical signal |
| Manufacturer Part Number | 15578 |
| OEM Part Number | MR985164 |
The Bosch 15578 is a direct-fit oxygen sensor intended to replace the factory unit on compatible Mitsubishi Eclipse engines. It measures exhaust oxygen concentration and sends an electrical signal to the engine control unit so air-fuel mixture and emissions control remain accurate. Bosch builds the sensor with a stainless steel, machined body and a fast-acting heater to reach operating temperature quickly, which helps reduce cold-start lean/rich errors and shortens catalyst light-off time. It is factory-tested and supplied with the correct connector and installation hardware to simplify swap-in replacement. Practical benefits include reliable long-term operation from corrosion-resistant construction and rapid warm-up for stable idle and better emissions during short trips. Limitations are that compatibility is limited to specific Eclipse model years and engine variants, and like all replacement sensors it requires correct vehicle fitment to avoid check-engine faults or drivability issues.
Best for: Performance-oriented Mitsubishi Eclipse owners who prioritize maintaining precise engine control and emissions performance with a high-quality, factory-quality replacement part.
Less Ideal for: Drivers who need a universal or multi-vehicle sensor solution or who are unsure of their exact Eclipse engine/production variant should consider alternatives or verify fitment before buying.
- Direct-fit design with factory-quality connectors for straightforward installation on compatible Mitsubishi Eclipse models
- Stainless steel body and machined exterior resist corrosion for longer service life
- Fast-acting heater reduces warm-up time for more accurate readings during cold starts
- Factory functional testing ensures the sensor operates within design specifications
- Only compatible with specific Mitsubishi Eclipse model years and engine configurations so fitment must be confirmed
Verdict A durable, fast-heating factory-quality oxygen sensor well suited for Mitsubishi Eclipse owners who want reliable, performance-minded replacement of the original unit.
4. Carock 2‑Piece Upstream and Downstream Oxygen Sensors for 2004–2012 Mitsubishi Eclipse / Galant 2.4L
| Brand | Carock |
|---|---|
| Material | Stainless Steel |
| Mounting Type | Flange Mount |
| Output Type | electrical signal |
These two Carock oxygen sensors replace the upstream and downstream units on 2004–2012 Mitsubishi Eclipse and Galant 2.4L engines to restore accurate exhaust oxygen measurement and fuel-trim control. They are intended as direct factory-quality replacements and install in the vehicle's existing flange mount locations using the original wiring harness. Notable features include a stainless steel, double laser-welded body for durability, a fast-acting heater for quicker warm-up, and a premium sensor tube aimed at delivering reliable electrical signal output to the engine computer. In everyday use the set helps the engine maintain the correct air/fuel ratio, which improves drivability and can prevent catalytic converter damage from long-term sensor failure. Important limitations are fitment sensitivity and connector differences between applications, so buyers must verify plug shape and sensor length before ordering; this is a budget-oriented aftermarket option rather than a factory-brand part. For a cost-conscious repair it provides the core function you need, but careful fit verification is required to avoid returns or incorrect installs.
Best for: Budget-conscious Mitsubishi Eclipse owners focused on an affordable, functional repair to restore proper engine fuel control and emissions monitoring.
Less Ideal for: Drivers seeking a long-term OEM-branded sensor or those unwilling to verify connector and length compatibility should consider higher-tier or dealer-sourced alternatives.
- Sold as an upstream and downstream pair so both sensors can be replaced at once
- Stainless steel double laser-welded body for improved durability in high-heat exhaust environments
- Built-in heater for faster sensor operation and quicker closed-loop fuel control
- Designed to match factory flange-mount installation for straightforward replacement
- Fitment depends on correct plug type and sensor length which vary by bank and position
- Aftermarket unit may not match long-term longevity of higher-end OEM-equivalent sensors
Verdict A cost-focused pair of upstream and downstream oxygen sensors that restore basic air/fuel monitoring for 2004–2012 Mitsubishi Eclipse 2.4L engines provided you confirm plug and length compatibility.
5. A-Premium Oxygen Sensor 4-PC Set for Mitsubishi Eclipse 2006-2012 (I4 2.4L)
| Vehicle Fitment | Mitsubishi Eclipse 2006-2012 I4 2.4L 4G69 |
|---|---|
| Set Quantity | 4-PC set |
| Measurement Range | 0% – 100% O2 |
| Measurement Accuracy | ±1.5% |
This four-piece A-Premium oxygen sensor kit replaces both upstream and downstream sensors on Mitsubishi Eclipse models with the 2.4L 4G69 engine. Each sensor reads exhaust oxygen content and sends an electrical signal to the engine control system so air/fuel mixture and emissions are adjusted correctly. The kit is marketed as a direct-fit replacement for the factory sensors and is intended for straightforward swap-in installation without modification. Practical benefits include restoring proper fuel trim and catalytic converter performance when original sensors age, and having all four locations covered in one purchase. The sensors list several OEM reference numbers for cross-checking fit and claim a measurement range covering 0 to 100 percent O2 with ±1.5% accuracy. Limitations are typical for aftermarket sensor kits: vehicle-specific compatibility must be confirmed against the listed reference numbers, and longevity and exact calibration can vary from factory-quality sensors which may affect long-term emissions control and diagnostics behavior on some vehicles.
Best for: Risk-averse mainstream buyers who prioritize restoring correct emissions and fuel control with a complete, straightforward replacement set for their Mitsubishi Eclipse 2.4L.
Less Ideal for: Drivers seeking an OEM-branded sensor or performance-tuned replacements should consider factory-quality or specialty options instead.
- Complete four-piece set covers upstream and downstream positions for a full sensor refresh
- Direct-fit design intended for quick installation without modifications
- Lists multiple OEM reference numbers for easier verification of vehicle compatibility
- Electrical output and full-range O2 measurement (0–100%) enable standard ECU control and diagnostics
- Aftermarket sensors can differ from factory-quality units in long-term durability and calibration
- No detailed durability or material specs provided to confirm lifespan
Verdict A convenient four-piece direct-fit sensor kit for Eclipse 2.4L owners who want a complete, install-ready replacement to restore emissions and fuel control.
6. Denso 234-4738 Oxygen Sensor
| Material | Zirconium |
|---|---|
| Mounting Type | Threaded |
| Output Type | Push-Pull |
The Denso 234-4738 is an upstream oxygen sensor that measures oxygen in the exhaust and reports that data to the engine control module to restore proper air-fuel management. It is typically used as a direct replacement when a factory sensor fails or triggers a check engine code on compatible Mitsubishi Eclipse models. Built with a zirconium sensing element, protective layers and a stainless steel housing, the unit is made to match factory fit and function and comes with a threaded mount and push-pull output for straightforward installation. Users report the connector, wire length, and fit match the original on Eclipse 2.4 and other compatible engines so it clears upstream O2 codes without additional tuning. The practical benefit is reliable, OEM-style performance without paying dealer prices. Limitations are that this is the upstream sensor only and must match the correct bank/location for your engine, and you will still need basic tools such as an oxygen sensor socket for removal and install.
Best for: Practical optimizers looking for a cost-effective, factory-quality replacement for a failed upstream oxygen sensor on a Mitsubishi Eclipse who prioritize correct fit and reliability over aftermarket tuning features.
Less Ideal for: Drivers who need a downstream sensor, want performance-tuning sensors with faster response characteristics, or prefer plug-and-play wireless diagnostics integrated into the sensor.
- Factory-quality design that matches factory fit and connector on many Mitsubishi Eclipse installations
- Zirconium sensing element with protective layers for accurate oxygen measurement
- Threaded mount and push-pull output for straightforward replacement
- Stainless steel housing and protective filters that improve durability in exhaust environments
- Sold as the upstream sensor only so incorrect bank/position selection will not fix downstream issues
- Requires an oxygen sensor socket and basic mechanical skill to install
Verdict A reliable, factory-style upstream replacement for Mitsubishi Eclipse owners who want OEM-like fit and function at a lower cost than dealer parts.
7. Bosch 18074 Premium Fitment Oxygen Sensor
| Brand | Bosch |
|---|---|
| Material | Stainless Steel |
| Mounting Type | Flange Mount |
| Output Type | Push-Pull |
| Item model number | 18074 |
This Bosch 18074 oxygen sensor is a direct-fit replacement meant to restore proper air-fuel sensing and emissions control on compatible Mitsubishi vehicles. It installs like a factory-quality part with pre-coated threads and a matching connector, so most DIYers can swap it in without special adapters. The sensor uses a stainless steel housing and an internal heater to reach operating temperature quickly, which helps the engine control module get accurate readings soon after startup and reduces warm-up emissions. Bosch tests each unit for functionality, so the part generally restores fuel trim behavior and can resolve check-engine codes tied to a failing sensor. Some users report excellent long-term durability while a small number have found gasket or fitment differences versus dealer parts, so careful inspection at install is wise. This is a sensible all-around pick when you want a tested, ready-to-install oxygen sensor that behaves like a factory replacement, but expect occasional variability in non-critical fit details compared with dealer-sourced sensors.
Best for: Balanced buyers who want a reliable, factory-style replacement for a Mitsubishi oxygen sensor that installs easily and restores normal engine operation without specialist help.
Less Ideal for: Customers who require guaranteed dealer-identical build quality or who prefer parts sourced directly from a Mitsubishi dealer should consider dealer-supplied sensors instead.
- True direct-fit connector and harness for simple installation
- Fast-acting heater reduces time to accurate readings after startup
- Stainless steel, sealed body for increased resistance to exhaust corrosion
- Factory-tested functionality to help restore fuel trim and emissions control
- Fitment or gasket quality can differ from dealer parts in some cases
Verdict A tested, ready-to-install Bosch direct-fit sensor that returns factory-like performance for Mitsubishi owners while offering good durability for most drivers.
Choosing the Right Mitsubishi Eclipse Oxygen Sensor: Key Factors to Consider
Exact Fitment and Connector Match
Correct thread size, heater lead configuration, and connector type are essential because improper fitment can cause leaks, electrical faults, or the need for splicing. A sensor that threads and plugs in like the original minimizes installation time and avoids adapter use, which can create mechanical or electrical failure points.
Always confirm whether the sensor is designated for the specific engine and exhaust routing of the Eclipse model year. Differences in upstream versus downstream placement or sensor bank assignment affect connector routing and harness length, so fitment prevents awkward cable runs and tension on the wiring.
Response Time and Signal Accuracy
Faster response times let the engine control unit correct fuel trim quickly, which improves idle stability, throttle response, and emissions. Sensors with stable, repeatable voltage swings or frequency outputs under changing load provide more reliable data for closed-loop control.
Signal accuracy matters more than claimed brand quality because poor or slow signals can trigger diagnostics and degrade performance. Look for sensors with documented response characteristics or technical specs that match the vehicle's original sensor behavior.
Heater Circuit Performance
A functioning heater helps the oxygen sensor reach operating temperature quickly, reducing the time the engine runs in open-loop mode after cold start. Heater reliability impacts cold-start emissions and initial drivability.
Consider sensors with robust heater elements and proper electrical connectors. If the heater circuit fails or is underspecified, the ECU may log heater-related error codes and the sensor will not reach proper operating temperature in a timely manner.
Durability and Contaminant Resistance
Exhaust environments expose sensors to high temperatures, soot, fuel deposits, and road debris. Sensors with protective coatings, durable ceramic elements, and sturdy housings resist contamination and thermal shock better.
Durability affects lifespan and long-term signal quality. A sensor that resists fouling and thermal degradation will maintain accurate readings longer, reducing the chance of repeat replacements and intermittent faults.
Placement: Upstream Versus Downstream Roles
Upstream sensors generally control fuel trim and must respond quickly to changes, while downstream sensors are used to monitor catalytic converter efficiency and can have different response characteristics. Choosing a sensor matched to its intended bank and position ensures the ECU receives the correct type of data.
Installing the wrong-characteristic sensor in the wrong position can lead to slow feedback or false catalyst fault indications. Confirm whether the part is specified for the correct bank and sensor position before purchasing.
Wiring, Harness Length, And Electrical Specs
Correct wiring length and connector orientation prevent stress on the harness and ensure secure routing away from heat sources and moving parts. Electrical specs such as heater resistance and signal wire shielding affect performance and noise immunity.
Poorly matched harnesses can cause signal degradation, intermittent faults, or require splicing that undermines reliability. Prefer sensors with documented electrical values and harnesses that align with the vehicle's factory routing to avoid installation compromises.
FAQ
How do I know if my Mitsubishi Eclipse oxygen sensor is failing?
Common signs include rough idle, decreased fuel economy, and a persistent check-engine indicator. You may also notice uneven acceleration or an engine that runs rich or lean at idle. Diagnostic trouble codes related to oxygen sensor response or heater circuits often accompany these symptoms.
Can I replace an oxygen sensor myself on a Mitsubishi Eclipse?
Many owners can handle the replacement with basic tools and proper safety precautions, such as lifting the car securely and allowing the exhaust to cool. Correct socket size and anti-seize on the threads are helpful. If wiring differences or sensor bank identification are unclear, professional help is advisable.
Should I replace both upstream and downstream sensors at the same time?
It depends on their condition. Upstream sensors typically wear faster and directly affect fueling, while downstream sensors monitor catalyst performance. If one sensor fails due to age or contamination, it may be sensible to inspect the others, but simultaneous replacement is not always necessary.
Will a bad oxygen sensor trigger a check engine light on my Eclipse?
Yes. Faulty sensor response or a failed heater circuit commonly cause the engine control unit to log a code and illuminate the check engine light. The exact code and whether the light stays on or blinks depends on the fault type and severity.
How do technicians test an oxygen sensor on this vehicle?
Technicians usually monitor the sensor's voltage or frequency response while the engine runs and compare it to expected switching behavior for the sensor type. They also check heater circuit resistance and wiring continuity. Dynamic testing under varied load can reveal slow response or signal dropouts.
Are aftermarket oxygen sensors reliable for the Mitsubishi Eclipse?
Aftermarket sensors can be reliable when they match the vehicle's fitment and electrical specifications. Prioritize units with documented compatibility, correct connectors, and clear electrical specs. Installation quality and correct positioning are also important for long-term performance.
How We Chose the Best Mitsubishi Eclipse Oxygen Sensor
We focused on parts that deliver correct fitment and reliable signal output for the Mitsubishi Eclipse. Key evaluation criteria included connector and thread compatibility with the vehicle, the sensor's ability to produce fast and stable voltage or frequency response under varied conditions, and robustness to heat and contaminants commonly encountered in exhaust systems. We also assessed wiring length and harness compatibility to avoid modification, and resistance to vibration and thermal cycling to ensure long-term operation. Electrical characteristics such as impedance and response time were reviewed to ensure they meet the ECU's expectations. Excluded from the list were general universal or adjustable sensors that require significant modification, and components lacking documented vehicle-specific fitment. We prioritized sensor attributes that actually affect drivability and emissions control rather than marketing claims.
Our full evaluation process is outlined in our review methodology.
Conclusion
When choosing a Mitsubishi Eclipse oxygen sensor, prioritize correct fitment, proper connector and harness length, and a sensor whose electrical and response characteristics match the vehicle's original unit. Balance the need for fast, accurate signals with durability against heat and contaminants. Consider placement and heater function as part of your decision, and make sure wiring and installation requirements are met to avoid diagnostic faults. Focusing on these factors will reduce drivability issues and help maintain emissions compliance over time.
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