Engine Error
P0139
O2 Sensor Circuit Slow Response (Bank 1 Sensor 2)
Severity
Low
Symptoms
Failed emissions, check engine light
Common Causes
- Contaminated O2 sensor tip
- Exhaust leak near the catalyst
- Aging oxygen sensor
- High resistance in sensor wiring
How to Fix
- 1 Replace downstream O2 sensor
- 2 Weld or replace leaking exhaust sections
- 3 Clean wiring harness connectors
Estimated Repair Cost
USD
$100
–
$300
O2 Sensor replacement: $150 - $300