P0167 — O2 Sensor Circuit No Activity Detected (Bank 2 Sensor 3)
Drive with caution — fix soon.
What P0167 means
This code means the bank 2 sensor 3 oxygen sensor signal is essentially flat, with no detectable activity, so the computer can't use it to monitor the exhaust. This commonly results from a failed sensor, a non-working sensor heater, or an open in the wiring or connector. The usual fix is replacing the oxygen sensor, but wiring, connector, and heater circuit faults should be checked first.
Common symptoms
- Check engine light is on
- Slightly reduced fuel economy
- Failed emissions or smog test
- Car usually still drives normally
- Oxygen sensor reads flat or inactive on a scan tool
Common causes
- Failed or dead oxygen sensor
- Non-working sensor heater preventing activity
- Open or broken wiring to the sensor
- Corroded, disconnected, or loose sensor connector
- Blown fuse affecting the sensor circuit
Typical repair cost
$150 – $400
Varies by vehicle and root cause.
Frequently asked questions
Can I keep driving with a P0167 code?
Usually yes, since an inactive rear sensor mainly affects emissions monitoring rather than drivability. Short trips are generally fine, though fuel economy may drop a little. Aim to have it diagnosed within a week or two so the sensor can resume its monitoring job.
How much does it cost to fix a P0167 code?
Most repairs fall between $150 and $400, covering the oxygen sensor and roughly an hour of labor. If the cause is just a fuse, connector, or section of wiring, it can be cheaper. A proper diagnosis confirms whether the sensor itself needs replacing.
Is a P0167 code serious?
It's a moderate concern. The vehicle stays drivable and safe, but without a working sensor the computer can't monitor that part of the exhaust, and you won't pass an emissions test. Fixing it promptly is the right move, though it's not an emergency.
What does no activity detected mean for this sensor?
It means the sensor's signal stays flat instead of fluctuating as it should when reading the exhaust. That can happen because the sensor has died, its heater never warms it up, or the wiring is broken, so the computer simply sees nothing useful coming from it.