Parts for your 2017 Subaru Exiga-Oxygen sensor

2017 Subaru Exiga oxygen sensor: what it does and when to replace it

Yes, the 2017 Subaru Exiga is fitted with oxygen sensors and they’re absolutely relevant to how the engine runs. Technical material from Subaru’s service information (STIS, Engine/Emission Control – Fuel Injection) specifies an upstream air–fuel ratio (A/F) sensor in the exhaust manifold and a downstream oxygen sensor after the catalytic converter. Major OEM suppliers’ catalogues (Denso, NGK/NTK) list both sensors for 2015–2018 Exiga/Crossover 7 2.0‑litre models, and emissions requirements aligned with ADR 79/04 (Euro 5) rely on closed‑loop oxygen sensing. Put simply, this model uses O2 sensing to meet fuel economy and emissions targets.

The oxygen sensor’s job is to help the ECU keep the mixture spot‑on. The front wideband A/F sensor constantly reports how rich or lean the burn is, letting the ECU trim fuel for smooth running and better kilometres per litre. The rear sensor keeps an eye on catalytic converter efficiency. When these two are healthy, cold starts are cleaner, throttle response feels crisp, and the cat lives a happier life.

They’re not a regular service item like oil or filters, but they do wear out with heat and age. Many workshops in Australia and New Zealand treat 160,000–200,000 km as a sensible window to test performance and consider proactive replacement, or earlier if there are fault codes (P0130–P0167 range), rough idle, higher fuel use, or a whiff of fuel from the exhaust. Blackened or sluggish sensor readings in live data are another giveaway.

Replacement is straightforward with the right tools. Use a quality 22 mm O2 socket, work on a warm (not hot) exhaust, and apply penetrating oil to help the threads. Always fit the correct OEM‑equivalent sensor (the front is a wideband A/F type, the rear a conventional O2 sensor), route the harness away from heat, and tighten to the torque in the Subaru service manual. After fitment, clear codes and let the ECU complete a few drive cycles to settle fuel trims.

Looking after the Exiga’s O2 sensors is cheap insurance: better fuel economy, lower emissions, and less chance of an early cat replacement. If the check engine light’s on or fuel economy’s gone pear‑shaped, a quick scan and sensor check is a smart first step.

• Common signs: check engine light, poor fuel economy, rough idle, failed WOF/rego emissions test.
• Good practice: inspect at major services, fix upstream air leaks, and use the correct octane and quality fuel.

Popular questions

How often should oxygen sensors be replaced on a 2017 Subaru Exiga?
They’re generally tested rather than replaced on a schedule. Many technicians will assess them around 160,000–200,000 km, or sooner if faults appear. If live data shows slow response or trims are maxed out, it’s time. Upstream sensors tend to wear faster than downstream ones due to hotter conditions.

What symptoms point to a failing oxygen sensor in an Exiga?
Expect a check engine light (often a P013x or P014x code), higher fuel use, sluggish throttle, sulphur or fuel smell from the exhaust, or an emissions test fail. A scan tool may show long‑term fuel trims drifting high or low and a lazy sensor waveform.

Can it be driven with a bad oxygen sensor?
Short term, the car will usually go into open‑loop or default trims and still run, but fuel economy and emissions suffer and the catalytic converter can be damaged if left too long. It’s best to diagnose and sort it promptly.