An oxygen sensor fault usually needs a check soon because it can affect fuel use and emissions.
Trouble codes · P0141
P0141 meaning
O2 Sensor Heater Circuit Bank 1 Sensor 2
The same first verdict Car Assist shows from this code alone, before a diagnosis. The code does not tell the app whether the warning light is flashing.
What this code doesn’t tell you
A code says where the car noticed a problem. It does not prove which part failed, whether the fault is still present, or what repair this car needs. The engine, other codes, freeze frame and live readings matter.
Usual causes, most likely first
The order is a starting point across cars; the exact engine and its readings can change it.
- Failed downstream oxygen sensor heater
- Damaged heater wiring or connector
- Blown heater fuse or supply fault
What you can check
With the engine off and cold, note recent exhaust work and any visible loose wiring from above. Have the heater supply tested before buying a sensor.
Words the car uses
- Stored codes
- Faults the car has confirmed and saved. They help explain a check-engine light, but a code alone does not prove which part needs replacing.
- Freeze frame
- A snapshot of the engine's readings when a fault was recorded. It helps show the conditions that caused the fault, even if the car now seems fine.
- Readiness monitors
- The car's own checks of its emissions systems. An unfinished check means the car has not tested that system yet, so a clean code scan may miss a fault.
- Oxygen sensor (O2)
- A sensor that measures oxygen in the exhaust. It helps control fuel use or check the catalytic converter; B1/B2 name cylinder groups and S1/S2 name sensor positions.
- Catalytic converter
- The catalytic converter cleans harmful gases from the exhaust. Faults here can affect emissions, and misfires can damage it.
Find out what’s causing yours
Car Assist reads your car through an OBD-II adapter and your iPhone. Its assistant uses the codes, freeze frame and live readings to work through the likely cause with you.