P0164
O2 Sensor Circuit High Voltage Bank 2 Sensor 3
Emissions / O2 sensor
Generic OBD-II
Medium
What it means
P0164 means the bank 2 sensor 3 (rear/downstream) oxygen sensor signal is staying too high — indicating a constant rich reading or a short in the circuit. This sensor is used for emissions monitoring rather than primary fuel control, so the engine still starts and usually drives normally. The main consequence is the check-engine light and a possible failed emissions test.
Medium
Can I keep driving? Safe to drive — this rear oxygen sensor is used for emissions monitoring; the engine starts and generally drives normally, though it may fail an emissions test.
Common symptoms
What you'll notice
- Check-engine light on
- Usually no noticeable change in how the car drives
- Possible slight drop in fuel economy
- May fail an emissions inspection
Common causes
Most likely first
- Failed or aged downstream oxygen sensor (bank 2, sensor 3)Likely
- Short-to-voltage or other wiring fault keeping the signal highCommon
- Corroded or loose sensor connectorCommon
- Sensor contaminationLess often
- Less commonly, an ECM/PCM faultLess often
How to diagnose & fix
Work through it in order
- Scan and read freeze-frame data, then check the live sensor voltage (a stuck-high reading confirms the fault).
- Inspect the signal wiring for a short-to-voltage and the connector for corrosion.
- Rule out an exhaust leak affecting the sensor.
- Replace the bank 2 sensor 3 oxygen sensor if it reads permanently high, then clear and retest.
FAQ
Quick answers
Is it safe to drive with P0164?+
Yes. This is a rear oxygen sensor used mainly for emissions monitoring, so driving is normal — but the car may not pass an emissions test until it's repaired.
Can I just clear P0164?+
You can, but it returns if the sensor or wiring is still faulty. A stuck-high signal usually means the sensor or a wiring short needs attention.
Related codes
Often seen with P0164
Read & clear P0164 yourself
Scan your car, confirm the code, and clear it once it's fixed — with OBD DashX on your phone.
✓ Verified name — SAE J2012 / ISO 15031-6Guidance reviewed by OBD DashX