Oxygen (lambda) sensors

P2275 Oxygen sensor: mixture too rich (bank 1, sensor 3)

By: Diagno editorial team · Updated: 2026-10-15

P2275 means: Oxygen sensor: mixture too rich (bank 1, sensor 3). The oxygen sensor measures oxygen in the exhaust and the computer sets the fuel mixture by it. OK to drive, but have it checked soon. The repair usually costs about €60–300 in Estonia. The most common cause: old or faulty oxygen sensor.

Is it safe to drive?OK to driveOK to drive, but have it checked soon.

Typical repair cost€60–300parts and labour in Estonia

What it means

The oxygen sensor measures oxygen in the exhaust and the computer sets the fuel mixture by it. Sensor 1 sits before the catalytic converter, sensor 2 after it. The computer found the signal wrong, slow or missing. Sensor 2 or 3 sits after the catalytic converter.

What you may notice

Engine light on
Higher fuel consumption
Idle may be uneven
Emissions may fail the inspection

What could be wrong

1Old or faulty oxygen sensor
2Exhaust leak ahead of the sensor
3Damaged wire or connector
4The mixture really is off (air leak or injector)

Repair difficulty: Moderate

What you can check yourself

Listen for an exhaust leak ahead of the sensor. Check that the sensor wire is intact and the connector is clipped in. You can do the simpler checks yourself.

How we fix it

We check the sensor signal and fuel trims on the diagnostic tool
We check for exhaust leaks
We replace the oxygen sensor if it is old or slow

Standard SAE description: O2 Sensor Signal Biased/Stuck Rich Bank 1 Sensor 3

This code usually comes with: Check engine lightSee what the light means →

Want a definite answer?

Bring the car to our workshop in Estonia for diagnostics. We read the fault codes, test the sensors and tell you what is wrong. Repair price depends on the work involved, generally €45 per hour.

Book a diagnostic check

Questions

What does fault code P2275 mean?

Oxygen sensor: mixture too rich (bank 1, sensor 3). The oxygen sensor measures oxygen in the exhaust and the computer sets the fuel mixture by it. Sensor 1 sits before the catalytic converter, sensor 2 after it. The computer found the signal wrong, slow or missing. Sensor 2 or 3 sits after the catalytic converter.

Can I drive with code P2275?

OK to drive, but have it checked soon.

How much does it cost to fix P2275?

Roughly €60–300 in Estonia. The price depends on exactly what has failed and on the car.

How is P2275 fixed?

We check the sensor signal and fuel trims on the diagnostic tool. We check for exhaust leaks. We replace the oxygen sensor if it is old or slow.

Based on AI combined with our hands-on workshop experience and knowledge. This information is general and prices are approximate (Estonian workshop rates). The same code can mean different things on different cars. Only an inspection of the car gives a definite answer.