Ask Andy AIP0133 O2 Sensor Circuit Slow Response (Bank 1 Sensor 1)
What it means, what causes it, and what it costs to fix.
What P0133 means
The upstream (front) oxygen sensor on bank 1 is switching between rich and lean too slowly. Usually it's just old and lazy.
Can I drive with P0133?
Severity: Low. Not urgent. Fix it when convenient.
Safe to drive, though fuel economy may drop.
Get a diagnosis for your exact car
Tell Andy your year, make, model, and symptoms. You'll get best case, most likely, and worst case, with parts and labor costs. Free, in about 15 seconds.
Ask Andy about P0133Symptoms
- Check engine light
- Reduced fuel economy
- Possible failed emissions
Common causes
Most likely first.
- Aging upstream O2 sensor (common past 80–100k miles)
- Exhaust leak near the sensor
- Sensor contaminated by oil or coolant
How to diagnose P0133
- Watch the O2 sensor in live data. A healthy sensor flips quickly between about 0.1 and 0.9 V.
- Check for exhaust leaks ahead of the sensor.
- If the engine burns oil or coolant, fix that or the new sensor will fail too.
Tip: most US auto parts stores will read your codes for free.
Repair costs
| Upstream O2 sensor | $150–$350 installed |
Typical US prices. Your vehicle, region, and shop rates will change these.
P0133 FAQ
What does P0133 mean?
P0133 means "O2 Sensor Circuit Slow Response (Bank 1 Sensor 1)." The upstream (front) oxygen sensor on bank 1 is switching between rich and lean too slowly. Usually it's just old and lazy.
Can I drive with a P0133 code?
Safe to drive, though fuel economy may drop.
What is the most common cause of P0133?
The most common cause is: Aging upstream O2 sensor. Other causes include exhaust leak near the sensor and sensor contaminated by oil or coolant.
How much does it cost to fix P0133?
Typical repairs run about $150 to $350 in the US, depending on the cause. Upstream O2 sensor: $150–$350 installed.
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