P0164 Code: O2 Sensor Circuit High Voltage (Bank 2 Sensor 3)
🟠 Moderate severity · drivable
Drivable, but the high sensor reading can affect emissions and fuel economy until it's fixed.
What P0164 means
The bank 2 sensor 3 oxygen sensor is sending a voltage that stays too high for too long. A high reading usually means the sensor is failing, its wiring is shorted to power, or the exhaust stream is unusually rich. This sensor sits after the catalytic converter.
Symptoms
- Check engine light is on
- Failed emissions test
- Slightly worse fuel economy
- Usually no noticeable driving symptoms
Common causes
- most common: Faulty downstream oxygen sensor
- common: Wiring shorted to power or damaged connector
- less common: Engine running rich
- less common: Exhaust leak near the sensor
How to fix it
| Fix | DIY? | Typical cost |
|---|---|---|
| Replace the bank 2 sensor 3 oxygen sensor | Yes | $60–200 |
| Repair or replace damaged wiring and connectors | Yes | $10–60 |
| Fix a rich-running condition or exhaust leak | Mechanic | $50–300 |
Frequently asked questions
Can I drive with a P0164 code?
Yes, the car is usually safe to drive. It mainly affects emissions and fuel economy, not safety.
What does "high voltage" mean on an O2 sensor?
The sensor signal stays near its high limit instead of swinging normally, which usually points to a bad sensor or a wiring short.
What is the most common cause of P0164?
A failed downstream oxygen sensor, with wiring shorts and a rich-running engine as the next most likely causes.
Related codes
P0162
P0162 Code: O2 Sensor Circuit Malfunction (Bank 2 Sensor 3)
P0163P0163 Code: O2 Sensor Circuit Low Voltage (Bank 2 Sensor 3)
P0166P0166 Code: O2 Sensor Circuit No Activity Detected (Bank 2 Sensor 3)
Updated 2026-08. This page is informational and not a substitute for professional diagnosis.