O2 Sensor Slow Response (Bank 1 Sensor 1)
Emission · Oxygen Sensors
The upstream Bank 1 oxygen sensor is switching between rich and lean too slowly. A healthy sensor should switch at least 8 times per 10 seconds at operating temperature — a slow sensor indicates aging or contamination.
- Aged, contaminated upstream O2 sensorMost common
- Oil or coolant contamination of sensorCommon
- Exhaust leak biasing the readingLess common
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Frequently asked questions about P0133
What does P0133 mean?
The upstream Bank 1 oxygen sensor is switching between rich and lean too slowly. A healthy sensor should switch at least 8 times per 10 seconds at operating temperature — a slow sensor indicates aging or contamination.
Is P0133 serious?
Safe to drive. Causes poor fuel trim accuracy and emissions test failure. Fix within 2–4 weeks.
How much does it cost to fix P0133?
Repair costs for P0133 range from $120 – $300 depending on the root cause and your vehicle.
Can I drive with P0133?
Yes, the vehicle is safe to drive. Schedule a repair at your convenience.