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Oxygen Sensors (O2 / Lambda)

Shop OEM replacement oxygen sensors for Toyota, Holden, Ford, Mitsubishi, Nissan, Hyundai, Kia, BMW, Mazda and more. Manufactured to OEM specifications for a direct plug-in fit. Use the Vehicle Part Finder to confirm the right sensor for your vehicle.

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Shop Our Oxygen Sensors (O2 / Lambda)

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What Does an Oxygen Sensor Do?

The oxygen sensor (also called a lambda sensor or O2 sensor) monitors the oxygen content in your exhaust gases and sends live data to your engine control unit (ECU). The ECU uses this data to maintain the correct air-fuel ratio for efficient combustion. Most vehicles have two to four sensors - upstream (pre-cat) sensors manage the fuel mix and downstream (post-cat) sensors monitor catalytic converter efficiency.

Symptoms of a Failing Oxygen Sensor

A faulty O2 sensor forces your ECU to run a default fuel map - usually running rich - which wastes fuel and increases emissions. Common symptoms include:

  • Noticeable drop in fuel economy
  • Rough or unstable idle
  • Hesitation or stumbling under acceleration
  • Rotten egg smell from the exhaust
  • Failed emissions test
  • Check Engine light with fault codes P0130 to P0167

Fitment and Technical Accuracy

Oxygen sensors vary significantly between makes and models - thread size, connector type, cable length, and sensor technology (narrowband vs wideband) all differ. Every sensor in our range is cross-referenced against OEM part numbers to ensure an exact match for your vehicle. Use the Vehicle Part Finder or filter by make and model to confirm fitment before ordering.

Why Buy From SensorGal?

SensorGal is a 100% Australian owned family business based in Cranbourne VIC stocking aftermarket OEM replacement oxygen sensors for Toyota, Holden, Ford, Mitsubishi, Nissan, Hyundai, Kia, BMW, Mazda, Subaru, Mercedes-Benz and Suzuki. Orders placed before 12 noon are dispatched same day via express post. All parts are backed by a 1-Year Australian warranty and our no-fuss returns policy.

Frequently Asked Questions

How do I replace an oxygen sensor?

Most O2 sensors thread directly into the exhaust pipe or manifold. You will need an O2 sensor socket (22mm with a slot for the wire) and penetrating oil if the sensor is seized. Allow the exhaust to cool completely before starting. Some sensors also require a wiring harness connector to be unplugged. Always clear fault codes with an OBD2 scanner after replacement.

What fault codes does a faulty O2 sensor trigger?

A faulty O2 sensor typically triggers codes P0130 to P0167. The specific code indicates which sensor has failed - P0130 to P0138 relate to Bank 1 sensors and P0150 to P0158 relate to Bank 2 sensors. An OBD2 scanner will identify the exact sensor location.

Can I use a universal O2 sensor on my vehicle?

Universal sensors can work but require splicing the wiring harness which introduces risk of connection faults. A direct-fit aftermarket OEM replacement sensor with the correct connector plugs directly in with no cutting or splicing required. SensorGal stocks direct-fit sensors cross-referenced to OEM part numbers for most Australian vehicles.

How do I know if my O2 sensor is bad?

Common signs include poor fuel economy, rough idle, failed emissions test, rotten egg smell from the exhaust, and a Check Engine light with codes P0130-P0167. An OBD2 scanner showing a flat or sluggish O2 sensor waveform on live data also indicates a faulty sensor.

What is the difference between upstream and downstream O2 sensors?

The upstream (pre-cat) sensor monitors exhaust gases to help the ECU calculate fuel trim. The downstream (post-cat) sensor monitors catalytic converter efficiency. They serve different functions and are not interchangeable even if they look identical.

Can a bad O2 sensor damage my catalytic converter?

Yes. A faulty upstream O2 sensor can cause the engine to run rich, sending unburnt fuel into the catalytic converter. Over time this overheats and destroys the catalyst. Replacing the O2 sensor promptly protects your catalytic converter.

How many O2 sensors does my vehicle have?

Most 4-cylinder vehicles have two O2 sensors (one upstream, one downstream). V6 and V8 engines typically have four - one upstream and one downstream per bank. Contact us with your vehicle details and we will confirm the correct quantity and part numbers.