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P0161: O2 Sensor Heater Circuit (Bank 2 Sensor 2)
Severity: Low Usually safe to keep driving, but get it checked.
What does P0161 mean?
The heater circuit for the bank 2, sensor 2 oxygen sensor (after the catalytic converter on the side opposite cylinder 1) has a fault. On some dual-exhaust V engines this is a separate sensor; on others the code may not be used. Like other heater codes, it concerns the built-in heater, not the oxygen signal itself.
Generic OBD-II definition: O2 Sensor Heater Circuit (Bank 2 Sensor 2). Confirm applicability in your vehicle service information.
Common causes
- Heater element burned out in the bank 2 downstream sensor
- Blown heater fuse
- Wiring or connector damaged under the vehicle
- Fault in the computer's heater driver (rare)
Symptoms
- Check engine light
- Usually no driveability change
Can I keep driving with P0161?
Severity: Low Usually safe to keep driving, but get it checked.
If the check engine light is flashing or the car runs badly, stop driving and have it checked.
Typical fixes
- Check for other heater codes; several at once points to a fuse or power feed
- Measure heater resistance at the sensor
- Inspect underbody wiring and the connector
- Replace the sensor if the heater reads open