P0133 Code: O2 Sensor Circuit Slow Response (Bank 1 Sensor 1)
🟠 Moderate severity · drivable
Drivable, but fuel control is sluggish, which can hurt economy and emissions.
What P0133 means
The bank 1 upstream oxygen sensor is responding too slowly to changes in the exhaust. A healthy sensor switches quickly; a slow one is usually aging or contaminated.
Symptoms
- Check engine light is on
- Reduced fuel economy
- Possible failed emissions test
Common causes
- most common: Aging or contaminated oxygen sensor
- common: Exhaust leak near the sensor
- less common: Oil or coolant contamination of the sensor
How to fix it
| Fix | DIY? | Typical cost |
|---|---|---|
| Replace the bank 1 upstream oxygen sensor | Yes | $60–200 |
| Repair an exhaust leak near the sensor | Mechanic | $50–200 |
Frequently asked questions
Can I drive with a P0133 code?
Yes, but fuel economy and emissions will suffer. Replace the sensor soon.
What is the most common cause of P0133?
An aging or contaminated oxygen sensor that has become sluggish.
How much does it cost to fix a P0133?
Typically $60–$200 for a new oxygen sensor.
Related codes
P0131
P0131 Code: O2 Sensor Circuit Low Voltage (Bank 1 Sensor 1)
P0132P0132 Code: O2 Sensor Circuit High Voltage (Bank 1 Sensor 1)
P0130P0130 Code: O2 Sensor Circuit Malfunction (Bank 1 Sensor 1)
Updated 2026-08. This page is informational and not a substitute for professional diagnosis.