Trouble codes › P0133
P0133 O2 Sensor Circuit Slow Response (Bank 1 Sensor 1)
Oxygen sensors
P0133 means bank 1's front oxygen sensor is responding too slowly, usually because it's old.
The front oxygen sensor on bank 1 is switching between rich and lean too slowly. Oxygen sensors get lazy with age, which makes the engine computer's fuel control less precise.
Safe to drive for now; fuel economy and emissions may suffer. Fix it before an emissions test.
Common causes
- An aging, slow oxygen sensor (most common, often over 100,000 miles)
- Contamination from oil, coolant or silicone
- An exhaust leak near the sensor
- Wiring or connector problems
Symptoms
- Check-engine light
- Slightly worse fuel economy
What to check first
- Check the sensor's age; original sensors past about 100,000 miles are often due.
- Look for exhaust leaks and signs of oil or coolant burning.
- Watch the sensor's switching speed with a scan tool.
- Replace with the correct sensor for your engine.
What does P0133 mean on your vehicle?
The likely cause depends on your engine. iRepair researches your exact year, make, model and engine (service bulletins, recalls and owner reports) and tells you what to check first. Your first 3 questions are free.
Ask iRepair about P0133No scanner? Most auto parts stores read check-engine codes for free.
Related codes
General guidance for P0133 on most vehicles. Some makers use the same code a little differently; confirm in the service information for your vehicle, put safety first, and see a professional when in doubt.