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P0133: Oxygen sensor (bank 1, sensor 1): slow response

The bank 1 oxygen sensor before the catalytic converter reacts too slowly to changes in the mixture. It is nearly always an ageing sensor.

Code P0133 at a glance
CodeP0133
SystemEngine and transmission
GroupP01xx, Air and fuel metering
TypeGeneric: it means the same on every make
Can you keep driving?With care

What P0133 means

The oxygen sensor before the catalytic converter measures how much oxygen is left in the exhaust, and the ECU uses that to fine-tune the air and fuel mixture. This code means the signal does change, but more slowly than it should, which is typical of a sensor with high mileage.

Most common causes

  • Oxygen sensor worn out by age and mileage
  • Sensor contaminated by oil, coolant or fuel additives
  • Exhaust leak close to the sensor
  • Poor contact in the connector or wiring
  • Air leak or misfires upsetting the exhaust gases

Symptoms

  • Engine warning light on
  • Higher fuel consumption than usual
  • Slightly rough idle or small hesitations
  • High emissions that can fail the inspection

Can you drive with P0133?

With care You can drive, but the mixture may not be controlled properly: fuel use goes up and, left too long, it can end up damaging the catalytic converter. Get it looked at soon.

How to check it

With the engine warm and slightly revved, watch the sensor voltage in live data: it should switch between lean and rich several times a second. If it rises and falls sluggishly, the sensor is tired.

How to read and clear P0133 with Final OBD

Plug an OBD2 scanner in under the steering wheel, switch the ignition on and open Final OBD. Under Faults you’ll see P0133 with this same explanation and whether it’s confirmed, pending or permanent.

With Free you read this code with its short description for nothing, and clear it if the engine stores it over standard OBD. With Pro you get the full explanation, how the car was running when it was logged (revs, temperature, load) and clearing in every control unit.

Clearing the code only turns the light off: if the cause is still there, it comes back. Clear it once it’s fixed, and not right before the ITV. It’s all in how to read and clear fault codes and in the ITV and OBD.

Similar codes

P0133 is a generic code, so it means the same on any make, for example on Abarth, Cupra, Jeep, Mini, Nissan, Seat. See what Final OBD does on your car in makes and models.

What does code P0133 mean?

The oxygen sensor before the catalytic converter measures how much oxygen is left in the exhaust, and the ECU uses that to fine-tune the air and fuel mixture. This code means the signal does change, but more slowly than it should, which is typical of a sensor with high mileage.

Can you drive with P0133?

You can drive, but the mixture may not be controlled properly: fuel use goes up and, left too long, it can end up damaging the catalytic converter. Get it looked at soon.

How do you clear P0133?

With an OBD2 scanner and an app like Final OBD, which clears it for free if it’s stored by the engine control unit. But clearing it only turns the light off: if the cause isn’t fixed, P0133 comes back.