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Emissions Sensors

Oxygen Sensor (O2 Sensor)

Measures oxygen concentration in exhaust gases and sends voltage signals to the engine computer, which adjusts the air-fuel mixture for optimal combustion, fuel economy, and emissions performance.

$100 – $350 per sensor

Total Cost

60,000 – 100,000 miles

Replace Interval

Moderate

DIY Difficulty

Schedule Soon

If It Fails

Overview

Oxygen sensors measure the oxygen content in exhaust gases, telling the engine computer whether the air-fuel mixture is too rich (too much fuel) or too lean (too much air). Most cars have 2-4 oxygen sensors.

Parts Cost

$30 – $150 per sensor

Labor Cost

$50 – $150 per sensor

Failure Symptoms

Check engine light (P0130-P0167 codes)
Moderate
Poor fuel economy
Low
Rough idle
Low
Failed emissions test
Moderate
Engine running rough or hesitating
Moderate
Black exhaust smoke (running rich)
Moderate

Warning Signs to Watch

  • Check engine light with O2 sensor codes
  • Fuel economy drop
  • Black smoke from exhaust
  • Failed emissions inspection

Common Causes of Failure

  • 1Normal degradation of the sensing element over time
  • 2Contamination from oil or coolant burning in the engine
  • 3Physical damage from road debris
  • 4Sensor wire damage
  • 5Carbon buildup on the sensor tip

Prevention Tips

  • Fix oil and coolant leaks that can contaminate sensors
  • Don't use fuel additives containing lead or silicon
  • Replace sensors at recommended intervals proactively
  • Keep the engine well-maintained to prevent rich/lean conditions

When to Replace

Replace when diagnosed as failed via check engine codes. Proactively replace at 100,000 miles as preventive maintenance.

Oxygen Sensor (O2 Sensor) by Make

Nissan oxygen sensors are a common failure point. Use Denso or NTK sensors for best results.

Denso sensors (OEM supplier for both brands) are the recommended replacement. They're affordable at $30-$60 each.

German car O2 sensors can be expensive — $80-$150 each. Bosch wideband sensors are the OEM supplier for most German vehicles.

Related Parts

Frequently Asked Questions

Need Oxygen Sensor (O2 Sensor) Replacement?

Get a free quote from a local mechanic. Average cost: $100 – $350 per sensor.

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