What usually causes it
- A dead oxygen sensor
- A broken wire or a loose plug
- A blown fuse for the sensor heater
- Damage from an exhaust leak or very hot exhaust
P0140Starts at: OK to drive, fix when convenient
Oxygen sensor shows no activity (bank 1, sensor 2)
The oxygen sensor checks the exhaust. The computer sees no changing signal from sensor 2, after the catalytic converter (the exhaust part that cleans the fumes), on bank 1.
Check this first
Check the fuse for the oxygen sensor heater. Your owner manual shows which fuse it is.
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 P0140 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 P0140
What does P0140 mean?
Oxygen sensor shows no activity (bank 1, sensor 2). The oxygen sensor checks the exhaust. The computer sees no changing signal from sensor 2, after the catalytic converter (the exhaust part that cleans the fumes), on bank 1.
Can I keep driving with P0140?
We rate P0140 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 P0140?
The most common causes, in order: A dead oxygen sensor; A broken wire or a loose plug; A blown fuse for the sensor heater; Damage from an exhaust leak or very hot exhaust.
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.