Pre-Cat Oxygen Sensor 8946730010 Toyota Corolla ZRE152 2ZR-FE Prius NHW20

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.

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.

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.

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.

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.

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.

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.