Parts for your 2018 Mitsubishi Eclipse cross-Oxygen sensor

2018 Mitsubishi Eclipse Cross oxygen sensor — what it does and how to look after it

Yes, the 2018 Mitsubishi Eclipse Cross is fitted with oxygen sensors. Technical documentation confirms this: the Mitsubishi Motors service manual for the 2018 Eclipse Cross (4B40 petrol) specifies a front air–fuel ratio (A/F) sensor and a rear heated oxygen sensor (HO2S) in the exhaust stream, Mitsubishi’s ASA electronic parts catalogue lists upstream and downstream sensor part numbers for GK-series Eclipse Cross, and major OEM suppliers’ catalogues (Denso, NTK/NGK) enumerate direct-fit sensors for this model. Modern OBD‑II/Euro 6 emission systems require these sensors to monitor and control fuel mixture and catalyst performance, so they’re very much relevant on this vehicle.

On the Eclipse Cross, the upstream A/F sensor sits before the catalytic converter and constantly measures exhaust oxygen so the ECU can fine‑tune the air–fuel mix for smooth running, good economy, and low emissions. The downstream HO2S sits after the cat to check the converter is doing its job. Together, they’re the quiet achievers that help the 1.5‑litre turbo petrol stay perky while keeping fuel bills and emissions in check.

There’s no strict replacement interval for oxygen sensors, but they are wear items. Many will go well past 150,000 km, some get lazy earlier due to contamination or exhaust leaks. If fuel economy drops, the check engine light pops up, the exhaust smells a bit off, or the car hesitates on light throttle, it’s worth scanning for codes and live data to see how the sensors are behaving.

• Tell‑tales of a crook sensor: increased fuel use, rough idle, sluggish performance, failed WOF/rego emissions, or codes like P0131/P0133/P0137.
• Good habits: fix any exhaust leaks pronto, avoid silicone‑based sealants near the intake/exhaust, and keep on top of air filter and spark plug servicing.
• When replacing: use OEM‑quality sensors, match the connector exactly, don’t touch the sensing tip, and follow the service manual torque spec. A smear of the correct anti‑seize on the threads (many new sensors come pre‑coated) helps the next change.

If the downstream sensor flags poor catalyst efficiency, don’t just throw a sensor at it—rule out rich running, misfires, or exhaust leaks first. A trusted workshop can check fuel trims and sensor switching with a scan tool to pinpoint whether it’s the sensor, wiring, or something upstream causing grief.

Looked after, the Eclipse Cross’s O2 sensors will keep the engine running sweet as and the emissions gear doing its bit for the long haul.

How many oxygen sensors are on a 2018 Eclipse Cross?

Generally two: a wideband A/F sensor before the catalytic converter and a heated oxygen sensor after it. Some market variants may differ, but the typical 1.5‑litre turbo petrol runs that upstream/downstream pair to manage fuelling and monitor the cat.

Can it be driven with a faulty oxygen sensor?

It’ll usually still run, but the ECU may default to a richer mixture. Expect higher fuel use, potential rough running, and a chance of catalyst damage if it’s left too long. Best to diagnose and sort it sooner rather than later.

What’s the typical lifespan of the Eclipse Cross oxygen sensors?

Many last 150,000–200,000 km, but life varies with fuel quality, driving profile, and leaks or contamination. If trims, switching rates, or response times look off on a scan, replacement can restore economy and drivability.