Parts for your 2017 Mitsubishi Asx-Oxygen sensor

2017 Mitsubishi ASX oxygen sensor — what it does and how to look after it

Based on technical references — Mitsubishi Motors Service Manual for ASX (2016–2017), Group 13A: Engine Control, the Mitsubishi ASA electronic parts catalogue, and Autodata service information — the 2017 Mitsubishi ASX sold in Australia and New Zealand (2.0L MIVEC petrol) is fitted with oxygen sensors. It uses a front air–fuel ratio (A/F) sensor in the exhaust manifold and a rear heated oxygen sensor (HO2S) after the catalytic converter. So yes, an oxygen sensor is relevant and used on the 2017 Mitsubishi ASX.

On this model, the oxygen-sensor setup constantly measures oxygen content in the exhaust so the engine control unit can fine‑tune fuelling. The front A/F sensor helps the ECU hit the stoichiometric sweet spot for smooth running, good power, and lower fuel use. The rear sensor checks catalytic converter efficiency. Together they help reduce emissions, avoid rough idle, and prevent that thirsty, sluggish feel.

There isn’t a fixed replacement interval for the 2017‑Mitsubishi‑ASX oxygen‑sensor — they’re replaced on condition. Typical life can be up to 160,000 km or more, but heat, poor fuel, or exhaust leaks can shorten that. Tell‑tales include a check‑engine light (often with codes like P0134, P0135, P0137, P0420), higher fuel consumption, sulphur smell, hesitation, or a lazy sensor trace on scan‑tool live data.

As part of routine servicing, it’s smart to visually check the sensor wiring and connectors, make sure there are no exhaust leaks upstream of the catalytic converter, and confirm trims and sensor activity with a scan tool. If replacement’s needed, stick with the correct spec A/F (front) and HO2S (rear) units for the 4B11 2.0L petrol. Fit with a proper O2‑sensor socket, avoid contaminating the tip, and tighten to the specified torque (about 40–45 N·m unless stated otherwise by Mitsubishi). Most new sensors arrive with the correct thread compound, don’t add extra anti‑seize unless the manufacturer specifies it.

DIYers can usually swap a rear sensor in the driveway, but a seized front sensor may need heat and care. After fitting, clear any fault codes and let the ECU relearn trims with a decent road drive. Keeping the oxygen sensors healthy helps the ASX stay economical, cleaner, and nicer to drive.

• Two sensors on AU/NZ 2017 ASX petrol: front A/F (manifold), rear HO2S (post‑cat)
• Check for wiring damage and exhaust leaks during each service
• Use the correct sensor type and torque, avoid contamination

FAQs

How many oxygen sensors does a 2017 Mitsubishi ASX have?
For the Australian and New Zealand 2017 ASX 2.0L petrol, there are two: a front air–fuel ratio sensor in the exhaust manifold and a rear heated oxygen sensor after the catalytic converter. Other markets and engines can differ.

When should the oxygen sensor be replaced on a 2017 ASX?
There’s no fixed kilometre interval. Replace when faulty or out of range — signs include a check‑engine light, higher fuel use, rough running, or catalyst‑efficiency codes. Many last well past 160,000 km if the exhaust is leak‑free and the engine is well maintained.

Can you drive with a bad oxygen sensor?
It’ll usually run, but fuel economy and performance can suffer, emissions rise, and the catalytic converter may be at risk if the mixture runs rich. Best to diagnose and repair promptly.