P0136 Code: O2 Sensor Circuit Malfunction (Bank 1 Sensor 2)
🟠 Moderate severity · drivable
Drivable, but the downstream sensor monitors the catalytic converter, so this should be fixed to pass emissions.
What P0136 means
The bank 1 downstream oxygen sensor (after the catalytic converter) isn't producing a usable signal. It monitors converter efficiency, so this is primarily an emissions concern.
Symptoms
- Check engine light is on
- Possible failed emissions test
- Usually no driving symptoms
Common causes
- most common: Faulty downstream oxygen sensor
- common: Exhaust leak near the sensor
- less common: Wiring or connector problem
How to fix it
| Fix | DIY? | Typical cost |
|---|---|---|
| Replace the bank 1 downstream oxygen sensor | Yes | $60–200 |
| Repair an exhaust leak near the sensor | Mechanic | $50–200 |
Frequently asked questions
Can I drive with a P0136 code?
Yes. It mainly affects emissions monitoring, not drivability.
What is the most common cause of P0136?
A faulty downstream oxygen sensor.
How much does it cost to fix a P0136?
Typically $60–$200 for a new downstream oxygen sensor.
Related codes
P0137
P0137 Code: O2 Sensor Circuit Low Voltage (Bank 1 Sensor 2)
P0138P0138 Code: O2 Sensor Circuit High Voltage (Bank 1 Sensor 2)
P0420P0420 Code: Catalyst System Efficiency Below Threshold (Bank 1)
Updated 2026-08. This page is informational and not a substitute for professional diagnosis.