Parts for your 2019 Mitsubishi Asx-Oxygen sensor

2019 Mitsubishi ASX oxygen sensor — what it does and when to sort it

Yes, the 2019 Mitsubishi ASX uses oxygen sensors, so the part is absolutely relevant for this model. Technical references indicate the ASX runs a front air–fuel ratio (A/F, wideband) sensor in the exhaust manifold and a rear heated oxygen sensor (narrowband) after the catalytic converter. These work together with the engine ECU to keep fuel mixtures spot-on and to monitor the cat’s efficiency.

• Mitsubishi Motors Service Manual (ASX/RVR/Outlander Sport, GA/AS platform, 2019), Group 11A Engine Electrical: Front Air–Fuel Ratio Sensor and Rear Heated Oxygen Sensor.
• Mitsubishi Electronic Parts Catalogue (ASA/EPC) for 2019 ASX models (e.g., GA2W/GK2W): upstream A/F sensor and downstream O2 sensor components listed.
• Australian Design Rule ADR 79/04 (Euro 5 equivalent): requires OBD catalyst monitoring, which uses a post-cat oxygen sensor.
• Major OE supplier catalogues (e.g., Denso) list direct-fit A/F and O2 sensors for 2019 ASX 2.0L MIVEC.

On the 2019 ASX, the oxygen sensor setup does the heavy lifting for clean running and decent fuel economy. The front A/F sensor feeds back rich/lean info so the ECU can trim fuel in real time, while the rear O2 sensor checks how well the catalytic converter is doing its job. When either sensor goes lazy or fails, expect a check engine light, higher fuel use, a bit of roughness, or even a failed rego/WOF emissions test.

There’s no fixed replacement interval in the factory schedule, they’re “replace when necessary” items. That said, wideband sensors often lose accuracy beyond the 120,000–160,000 km mark. For anyone clocking up the kays, it’s smart to plan inspection on major services after 100,000 km. A scan tool check of fuel trims and sensor response, plus a quick look for exhaust leaks, goes a long way.

If replacement’s on the cards, stick with quality, direct-fit parts. Universal splice-in options can introduce wiring resistance issues and false readings. Avoid contaminating the sensing tip with oils or silicone sprays, and don’t drop the sensor. Most new sensors come with the right thread compound pre-applied, if not, use only sensor-safe anti-seize and tighten to the service manual spec. After fitting, clear fault codes and perform a proper drive cycle so the ECU can relearn trims and run its catalyst tests. Also worth doing: fix any exhaust leaks ahead of the cat, keep the air filter fresh, and address misfires promptly — all of which help your sensors and cat live longer.

Popular questions about the 2019 Mitsubishi ASX oxygen sensor

How many oxygen sensors are on a 2019 ASX?
Most AU/NZ 2019 petrol ASX models have two: a front air–fuel ratio (wideband) sensor in the manifold and a rear heated oxygen sensor after the catalytic converter. Variations by market or engine can exist, so a VIN-based parts check is best if unsure.

When should the oxygen sensor be replaced?
There’s no set interval. Replace when symptoms or diagnostics point to a fault — think check engine light with codes like P0134, P0137, P0138, or P0420, poor fuel economy, or failed emissions. Many sensors remain healthy past 120,000–160,000 km, but accuracy can drift with age and contamination.

Can the ASX be driven with a bad oxygen sensor?
It will usually still run, but fuel economy suffers, emissions go up, and long-term you risk damaging the catalytic converter. It’s best to diagnose and fix sooner rather than later to avoid bigger bills.