Parts for your 2019 Mitsubishi Eclipse cross-Oxygen sensor

2019 Mitsubishi Eclipse Cross oxygen sensor — what it does and when to service it

Yes, the 2019 Mitsubishi Eclipse Cross is fitted with oxygen-sensing hardware. Mitsubishi’s factory service information for the Eclipse Cross (GK series, 2018–2020, Engine and Emission Control/Group 13A) specifies an upstream air–fuel ratio (A/F) sensor and a downstream heated oxygen sensor (HO2S). That aligns with Australian and New Zealand emissions compliance (ADR 79/04/Euro 5-equivalent), which requires closed-loop lambda control and on‑board diagnostics that rely on oxygen sensors. Parts catalogues for the 1.5‑litre turbo petrol also list separate front A/F and rear O2 sensors, confirming the fitment on this model.

On this vehicle, the upstream A/F sensor sits before the catalytic converter and continuously measures the exhaust’s oxygen content to keep the air–fuel mixture right on the money. The ECU uses that signal to trim fuel on the fly for smooth driving, solid performance and better fuel economy. The rear HO2S sits after the cat and primarily monitors catalytic converter efficiency, it’s how the ECU knows the cat is doing its job and flags faults with a check engine light if it isn’t.

While oxygen sensors aren’t a regular “every service” replacement item, they’re critical for emissions and economy. Over time (often past 150,000–200,000 km), sensors can become “lazy” due to contamination from oil vapour, coolant, silicone sealants or leaded additives, causing higher fuel use, rough idle, hesitation or a sulphurous smell. A scan tool reading long- and short‑term fuel trims, plus live lambda data and heater operation, is the smart way to confirm condition before replacement.

For routine servicing of a 2019 Eclipse Cross, a workshop should:

• Check for stored fault codes (P013x/P014x ranges) and inspect wiring, connectors and exhaust leaks ahead of the sensor.
• Verify live sensor response and heater function rather than guessing.
• If replacement is needed, use OE‑quality parts (the front is a wideband A/F sensor, the rear a conventional HO2S) and match connectors exactly.
• Only remove sensors from a cool exhaust, use proper O2-sensor sockets, avoid twisting the harness, and tighten to the manufacturer’s torque spec. Most new sensors arrive with pre‑coated threads—don’t add extra anti‑seize unless the manufacturer specifies it.
• After fitting, clear codes and confirm closed‑loop operation and stable trims on a warm road test.

Treating the oxygen sensors as precision components keeps the Eclipse Cross sipping petrol sensibly, passes WOF/rego emissions checks with less fuss, and protects that pricey catalytic converter.

Popular questions

How many oxygen sensors are on a 2019 Mitsubishi Eclipse Cross?
Petrol Eclipse Cross models typically have two: an upstream wideband air–fuel ratio sensor before the catalytic converter and a downstream heated oxygen sensor after it. That layout lets the ECU control mixture accurately and verify catalytic converter efficiency.

When should the oxygen sensor be replaced?
There’s no fixed interval. Replace when diagnostics show slow response, heater faults or out‑of‑range signals, or if contamination is evident. Many sensors last well past 150,000 km, but age, short-trip driving and oil or coolant exposure can shorten life. A proper scan of fuel trims and live data should guide the call.

Can an oxygen sensor be cleaned instead of replaced?
No. Solvents, wire brushing or “cleaning” often ruin the sensing element. If testing confirms a faulty or contaminated sensor, replacement with an OE‑quality part is the reliable fix. Also avoid silicone sealants upstream of the sensor, as vapours can poison it.