Oxygen sensor heater
P0155
Oxygen Sensor Heater Circuit (Bank 2 Sensor 1)
The small heater inside an oxygen sensor isn't working. The heater gets the sensor up to temperature quickly after a cold start.
Fine to drive
Can I keep driving? Yes, in most cases. It won't hurt the car in the short term, but get it fixed. A check engine light that's already on can't warn you about a new problem. The car drives normally. Fuel economy and emissions are a little worse until the engine warms up, and it will fail an emissions test.
What the words mean
- Bank 2 is the side of a V engine that doesn't have cylinder 1.
- Sensor 1 is the oxygen sensor before the catalytic converter.
Common causes
- The sensor's heater has burned out (the usual cause on an older sensor)
- A blown fuse for the heater circuit
- Damaged wiring or a corroded connector near the exhaust
Listed roughly from most to least likely. The same code can have different causes on different cars.
What to do
- Check the fuse for the oxygen sensor heaters.
- Look at the wiring near the exhaust for melted or rubbed-through spots.
- Replace the sensor named in the code if the wiring is sound.
General guidance. Your owner's manual wins. If a red warning light is on or the car drives differently, stop safely and get help.
Related codes
- P0030Oxygen Sensor Heater Control Circuit (Bank 1 Sensor 1)
- P0031Oxygen Sensor Heater Control Circuit Low (Bank 1 Sensor 1)
- P0036Oxygen Sensor Heater Control Circuit (Bank 1 Sensor 2)
- P0037Oxygen Sensor Heater Control Circuit Low (Bank 1 Sensor 2)
- P0050Oxygen Sensor Heater Control Circuit (Bank 2 Sensor 1)
- P0135Oxygen Sensor Heater Circuit (Bank 1 Sensor 1)
- P0141Oxygen Sensor Heater Circuit (Bank 1 Sensor 2)
- P0161Oxygen Sensor Heater Circuit (Bank 2 Sensor 2)
Track this automatically in Tagwell Auto
Tagwell Auto keeps your car's service dates and mileage, so when a code shows up you know what was done last. With a Bluetooth reader for the car's diagnostic port (called OBD-II), the phone app can read the code itself.