P0159: O2 Sensor Circuit Slow Response (Bank 2 Sensor 2)
Can you still drive? Yes, the vehicle is safe to drive. However, fuel economy may suffer and you may fail an emissions test.
What Does P0159 Mean?
Code P0159 indicates that the downstream oxygen sensor on bank 2 is responding too slowly to changes in the exhaust gas oxygen content. The ECM monitors the switching rate of the sensor and sets this code when the response time exceeds a calibrated threshold. A sluggish sensor cannot accurately monitor catalytic converter efficiency.
Need to read your codes?
An OBD-II scanner lets you read and clear diagnostic trouble codes from your vehicle's computer. Most scanners work with any car made after 1996.
Browse OBD-II Scanners on AmazonCommon Causes
- Aging or contaminated O2 sensor
- Exhaust leak near the sensor
- Wiring damage or corrosion at the sensor connector
- Fuel contamination from oil burning
Symptoms
- Check engine light on
- Reduced fuel efficiency
- Slight increase in exhaust emissions
- Rough idle at times
Diagnostic Steps
- 1Read and record freeze frame data
- 2Monitor O2 sensor waveform with a scan tool
- 3Compare Bank 2 Sensor 2 response rate to manufacturer specs
- 4Inspect wiring and connector for corrosion or damage
- 5Check for exhaust leaks around the sensor
Recommended Parts & Tools
oxygen sensor
O2 sensor socket wrench
Estimated Repair Cost
| Type | Estimated Cost |
|---|---|
| Total Repair Cost Range | $100 - $350 |
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Frequently Asked Questions
What does a slow O2 sensor response mean?
It means the oxygen sensor is taking too long to switch between rich and lean readings, which reduces its ability to monitor exhaust quality and converter performance.
Can I replace the O2 sensor myself?
Yes, with an O2 sensor socket and basic tools most DIYers can replace a downstream O2 sensor in under an hour.
Will P0159 cause emissions failure?
Yes, P0159 will cause your vehicle to fail an emissions inspection in most states.
Community Fix Reports
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