Parts for your 2021 Mitsubishi Outlander-Oxygen sensor

2021 Mitsubishi Outlander oxygen sensor: what it does and how to look after it

Yes, the 2021 Mitsubishi Outlander is fitted with oxygen sensors. Technical documentation confirms it: the Mitsubishi Outlander Workshop Manual (GF/GG series, Group 13 Fuel) specifies a front air–fuel ratio (A/F) sensor and a rear heated oxygen sensor (HO2S) for the 2.4L petrol and PHEV variants. OEM parts catalogues (Mitsubishi ASA/EPC, common listings include front A/F sensor and rear HO2S under part families such as 1588A9xx) and major aftermarket catalogues from NGK/NTK and Bosch also list these sensors for MY2021. Compliance with ADR 79/04 (Euro 5/6-equivalent) further necessitates upstream mixture control and downstream catalyst monitoring, both achieved with O2 sensors.

On the 2021 Outlander, the front wideband A/F sensor constantly measures how rich or lean the exhaust mixture is, letting the ECU trim fuel for smooth running, decent economy, and low emissions. The rear sensor sits after the catalytic converter to keep tabs on catalyst efficiency. Petrol models and the PHEV both rely on this setup, even when the PHEV’s engine runs less often, it still needs accurate lambda feedback whenever it fires up.

These sensors aren’t a routine replacement item in the maintenance schedule, but they are wear components. Ageing, silicone or coolant contamination, oil burning, or exhaust leaks can slow response or skew readings. As part of regular servicing on a 2021 Outlander, a savvy workshop will:

• Scan for fault codes and check fuel trims and sensor activity (front sensor should be responsive, rear should show stable post-cat behaviour).
• Inspect for exhaust leaks ahead of the sensors and check wiring and connectors for heat damage.
• Update the ECU and clear trims after repairs where applicable.

Common signs of a crook O2 sensor include a check engine light (codes like P0134, P0137, P0420), rough idle, increased fuel use, sulphur smell, or a failed emissions/WOF test. If replacement is needed, quality matters, fit the correct wideband A/F sensor or HO2S specified for the Outlander’s VIN. Use an O2 sensor socket, avoid twisting the loom, and follow manufacturer torque and anti-seize guidance (many sensors ship with pre-applied compound). After installation, clear codes and perform a short drive so the ECU can relearn. Many owners see reliable service well past 160,000 km, but if trims are out or response is lazy, proactive replacement can restore economy and keep the cat happy.

Popular questions

How many oxygen sensors does a 2021 Mitsubishi Outlander have?
Most 2021 Outlanders have two: a front wideband A/F sensor before the catalytic converter and a rear heated oxygen sensor after it. Some market/engine variants can differ slightly, but petrol and PHEV models typically follow this two-sensor layout.

Where are the sensors located on the 2021 Outlander?
The front A/F sensor threads into the exhaust manifold or the front pipe just below it, visible from the engine bay on most models. The rear HO2S is mounted in the exhaust pipe after the catalytic converter, usually accessed from underneath on a hoist.

Should the oxygen sensor be replaced as preventative maintenance?
There’s no fixed interval in the factory schedule. If diagnostics show slow response, high fuel trims, or related fault codes, replacement makes sense. Many technicians consider refreshing the front sensor somewhere around the 150,000–200,000 km mark if performance or economy has tailed off.