What usually causes it
- A worn out or failed oxygen sensor
- A loose plug, or burned or chewed wires near the sensor
- An exhaust leak near the sensor
- A worn catalytic converter
P0156Starts at: OK to drive, fix when convenient
Oxygen sensor signal problem (bank 2, sensor 2)
The oxygen sensor checks the exhaust. Sensor 2 sits after the catalytic converter (the exhaust part that cleans the fumes) on the side of the engine without cylinder 1, and its signal looks wrong.
Check this first
Listen for ticking or hissing from the exhaust, which points to a leak, before you buy a new sensor.
What to watch for
- A rotten egg smell from the exhaust
- Poor gas mileage
- A flashing check engine light, which means a bad misfire
Can I keep driving?
We rate P0156 as OK to drive, fix when convenient, as a starting point. Keep an eye on the signs below. If the light starts flashing, stop driving soon.
Quick answers about P0156
What does P0156 mean?
Oxygen sensor signal problem (bank 2, sensor 2). The oxygen sensor checks the exhaust. Sensor 2 sits after the catalytic converter (the exhaust part that cleans the fumes) on the side of the engine without cylinder 1, and its signal looks wrong.
Can I keep driving with P0156?
We rate P0156 as OK to drive, fix when convenient, as a starting point. Keep an eye on the signs below. If the light starts flashing, stop driving soon.
What usually causes P0156?
The most common causes, in order: A worn out or failed oxygen sensor; A loose plug, or burned or chewed wires near the sensor; An exhaust leak near the sensor; A worn catalytic converter.
Estimates only. A mechanic should confirm. The same code can mean slightly different things on different cars; the app explains it for your exact year, make, model and mileage.