Parts for your 2025 Mitsubishi Eclipse cross-Oxygen sensor

2025 Mitsubishi Eclipse Cross oxygen sensor: what it does and how to look after it

Yes—an oxygen sensor is fitted to the 2025 Mitsubishi Eclipse Cross and it’s highly relevant. Technical sources confirm it’s standard equipment on both the 1.5‑litre turbo petrol and the PHEV’s petrol engine. Mitsubishi workshop manuals for the Eclipse Cross (GK/GL series) specify a front Air/Fuel (A/F) ratio sensor and a rear heated oxygen sensor (HO2S) for closed‑loop fuelling and catalytic converter monitoring. The Mitsubishi ASA global parts catalogue lists these sensors for Eclipse Cross model years spanning to 2025. Regulatory requirements also support this: Australian Design Rule ADR 79 (Euro 5/6 equivalent) and OBD‑II emissions monitoring expect pre‑ and post‑catalyst oxygen sensing on petrol vehicles.

On the 2025 Eclipse Cross, the front A/F sensor sits in the exhaust manifold or upper downpipe to measure the oxygen content of exhaust gas in real time. The engine control unit uses that signal to trim fuelling, keeping the air‑fuel mixture right on the money for smooth running, strong economy, and low emissions. The rear HO2S, mounted after the catalytic converter, keeps an eye on converter efficiency. That pair works together so the ECU can quickly adjust under changing loads—whether that’s the daily commute or a weekend run up the coast.

There’s no fixed service interval for oxygen sensors on this model, but they are wear items. On Aussie and Kiwi roads, many will last 150,000–200,000 km. PHEV owners might see slower ageing thanks to more engine‑off operation, but the sensors still age with heat cycles and fuel quality. During regular servicing, a technician should:

• Scan for OBD‑II fault codes (e.g., P0131–P0161 range/performance, heater, or response faults).
• Check fuel trims and sensor switching behaviour with live data.
• Inspect wiring, connectors, and exhaust leaks that can skew readings.

Typical warning signs include rough idle, lazy throttle response, higher fuel use, a sulphur smell, or an illuminated check‑engine light. If replacement’s needed, go with the correct spec sensor (front A/F vs rear HO2S aren’t interchangeable), follow the factory torque procedure, and avoid adding anti‑seize unless the new sensor is supplied without a pre‑applied coating. A proper fix restores crisp drivability and keeps emissions gear happy—no mucking about.

Pro tip for DIYers: disconnect the battery only if the service manual calls for it, avoid twisting the harness, and always clear codes and confirm repair with a warm‑up drive and post‑repair scan.

Popular questions

How many oxygen sensors does a 2025 Eclipse Cross have?
Most petrol 1.5T versions use two: a front A/F sensor before the catalytic converter and a rear heated oxygen sensor after it. The PHEV’s petrol engine also uses the same upstream/downstream arrangement for accurate fuelling and catalyst monitoring. Some market or trim variations can differ, but two is the common setup.

When should the oxygen sensors be replaced?
They’re not usually a scheduled replacement item. Plan on testing rather than guessing: replace if fault codes appear, fuel economy drops, drivability suffers, or live data shows slow response. Many sensors last 150,000–200,000 km, PHEV usage patterns can extend that, but heat and age still win eventually.

Can oxygen sensors be cleaned, or do they need replacing?
Cleaning rarely restores proper function and can damage the sensing element. If a sensor is slow, biased, or has heater faults, replacement with a quality, correct‑type sensor is the reliable fix. Always reset adaptations and confirm with a road test and scan.