P0136 — O2 Sensor Circuit Malfunction (Bank 1 Sensor 2)
Can drive — fix at your convenience.
What P0136 means
This code means the engine computer detected a fault in the circuit for the downstream oxygen sensor (Bank 1, Sensor 2), the one after the catalytic converter. It often comes down to a failed sensor, damaged wiring, or a loose connector, though exhaust leaks can also trigger it. The fix is usually straightforward and most commonly involves replacing the oxygen sensor.
Common symptoms
- Check engine light is on
- Slightly reduced fuel economy
- Failed emissions or smog test
- No noticeable change in how the car drives
- Occasional faint smell of fuel or exhaust
Common causes
- Failed downstream oxygen sensor
- Damaged or corroded wiring to the sensor
- Loose or dirty electrical connector
- Exhaust leak near the sensor
- Less commonly, a problem with the engine computer
Typical repair cost
$150 – $400
Varies by vehicle and root cause.
Frequently asked questions
Can I keep driving with a P0136 code?
Usually yes, at least for short-term driving. This sensor monitors emissions rather than controlling the engine, so the car should run normally. Still, have it checked within a week or two and don't skip an emissions test, since the car will likely fail one.
How much does it cost to fix a P0136 code?
Most repairs land between $150 and $400. The oxygen sensor itself is the biggest cost, and labor is usually modest since the sensor is fairly accessible. Wiring or connector repairs can be cheaper if the sensor turns out to be fine.
Is a P0136 code serious?
It's generally a low-severity code. It won't strand you or quickly damage the engine, but it does affect emissions monitoring and can hurt fuel economy slightly. Address it before it leads to a failed inspection or hides a related issue.
What does Bank 1 Sensor 2 mean for P0136?
Bank 1 is the side of the engine with the number 1 cylinder, and Sensor 2 is the oxygen sensor located after the catalytic converter. This sensor mainly checks whether the converter is doing its job, which is why a fault here is more about emissions than performance.