Part and system guide
Oxygen Sensors
Oxygen sensors monitor exhaust oxygen so the engine computer can adjust fuel mixture and catalyst checks.
What it does
Help control fuel trim and emissions monitoring.
Failure signs
- Check engine light
- Poor fuel economy
- Failed emissions test
- Lean or rich codes
- Slow sensor response
Maintenance notes
- Fix vacuum leaks and misfires before blaming sensors.
- Identify upstream versus downstream sensor location.
- Inspect wiring close to hot exhaust.