P0159
O2 Sensor Circuit Slow Response (Bank 2 Sensor 2)
Moderateoxygen sensor
Overview
The P0159 diagnostic trouble code indicates a o2 sensor circuit slow response (bank 2 sensor 2) condition. Oxygen sensors monitor the oxygen content in the exhaust stream and provide feedback to the PCM for precise fuel mixture control. A malfunction in the O2 sensor circuit can result in poor fuel economy, increased emissions, and potential catalytic converter damage.
Symptoms
- Rough engine idle
- Black smoke from exhaust
- Failed emissions test
- Reduced engine performance
Common Causes
- Failed or aging oxygen sensor
- Damaged O2 sensor wiring or connector
- Faulty O2 sensor heater circuit
- Incorrect sensor installed
Diagnosis Steps
- 1Connect an OBD-II scanner and read all stored trouble codes and freeze frame data
- 2Monitor the O2 sensor readings using live data on the scan tool
- 3Inspect the O2 sensor wiring and connector for damage or corrosion
- 4Test the O2 sensor heater circuit with a multimeter
- 5Check for exhaust leaks near the O2 sensor location
Estimated Repair Cost
$100 — $400
Cost varies by vehicle, location, and repair shop. Includes parts and labor.
Commonly Affected Vehicles
Ford FusionHonda CivicMazda 3Volkswagen Jetta
Related Codes
More Oxygen Sensor Codes
P0030HO2S Heater Control Circuit (Bank 1 Sensor 1)
ModerateP0031HO2S Heater Control Circuit Low (Bank 1 Sensor 1)
ModerateP0032HO2S Heater Control Circuit High (Bank 1 Sensor 1)
ModerateP0036HO2S Heater Control Circuit (Bank 1 Sensor 2)
ModerateP0037HO2S Heater Control Circuit Low (Bank 1 Sensor 2)
LowP0038HO2S Heater Control Circuit High (Bank 1 Sensor 2)
ModerateFrequently Asked Questions
Most O2 sensors should be replaced every 60,000-100,000 miles as preventive maintenance. Heated O2 sensors may last longer, but performance gradually degrades with age.