Note: Pos 2 is pre converter at manifold, Pos 3 is after converter in pipe.
What They Do: Measure the amount of oxygen in exhaust and signal computer to adjust air/fuel ratio.
Failure Symptoms: Low voltage output or slow reaction causes poor performance and economy, high emissions.
Maintenance/Service: Perform periodic emissions checks. Replace according to manufacturer's specifications or every 25,000-30,000 miles. Watch for service flag or Malfunction Indicator Lamp.
Electrical components such as sensors are non-returnable parts.
Always refer to a factory service manual when diagnosing engine service problems. You can damage electrical components if the proper procedures are not followed. Be sure youare replacing the correct part.