Symptoms of faulty oxygen sensor:
- Check engine light on
- Poor fuel economy
- Rough idle or hesitation
- Failed emissions test
- Scan for fault codes (common codes: P0130, P0131, P0132)
- Check sensor wiring for damage
- Test sensor voltage output
- Inspect exhaust for leaks near sensor
- Locate faulty sensor (pre-cat or post-cat)
- Disconnect electrical connector
- Remove sensor using oxygen sensor socket
- Install new sensor (do not use anti-seize on thread)
- Reconnect electrical connector
- Clear fault codes and test
- Use OEM or high-quality aftermarket sensors
- Be careful not to damage threads in exhaust
- Allow engine to fully cool before replacement
