A dead oxygen sensor. A failed heater, so the sensor never warms up (check for heater codes). An open signal wire or corroded connector. An exhaust leak near the sensor.

Trouble codes › P0134

P0134 O2 Sensor Circuit No Activity Detected (Bank 1 Sensor 1)

Q: What does P0134 mean?

P0134 means bank 1's front oxygen sensor isn't switching at all, usually a dead sensor or a failed heater. The front oxygen sensor on bank 1 isn't switching at all: the engine computer sees a flat signal, usually around the middle of its range.

Oxygen sensors

P0134 means bank 1's front oxygen sensor isn't switching at all, usually a dead sensor or a failed heater.

The front oxygen sensor on bank 1 isn't switching at all: the engine computer sees a flat signal, usually around the middle of its range.

Can I keep driving? Yes, but get it fixed soon.

Usually drivable, but the engine is running without its main fuel feedback. Get it fixed soon.

Common causes

A dead oxygen sensor
A failed heater, so the sensor never warms up (check for heater codes)
An open signal wire or corroded connector
An exhaust leak near the sensor

Symptoms

Check-engine light
Worse fuel economy
Sometimes rough running

What to check first

Check for heater codes (P0135, P0030, P0031) too.
Inspect the wiring and connector.
Watch the sensor on a fully warm engine; a flat reading means it's not working.
Replace the sensor if the wiring is good.

What does P0134 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 P0134

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Related codes

General guidance for P0134 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.