Oxygen (lambda) sensors

P1134 Oxygen sensor transition time ratio wrong (bank 1, sensor 1)

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

P1134 means: Oxygen sensor transition time ratio wrong (bank 1, sensor 1). 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 most common repair costs about €90–180 in Estonia, depending on make and model.

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

Oxygen sensor replacement€90–180parts and labour in Estonia, depending on make and model

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.

This is a make-specific code (GM). The exact meaning can vary by model and year.

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 · Oxygen sensor replacement €90–180
2Exhaust leak ahead of the sensor · Sensor replacement €80–160
3Damaged wire or connector · Wiring or connector repair €45–90
4The mixture really is off (air leak or injector) · Leak check and hose or gasket replacement €60–120

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: HO2S Transition Time Ratio (Bank 1 Sensor 1)

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 P1134 mean?

Oxygen sensor transition time ratio wrong (bank 1, sensor 1). 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.

Can I drive with code P1134?

OK to drive, but have it checked soon.

How much does it cost to fix P1134?

It depends on the cause: oxygen sensor replacement €90–180; sensor replacement €80–160; wiring or connector repair €45–90. Prices include labour at €45/h, depending on make and model.

How is P1134 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.