OBD-II code guide
P0134 Oxygen Sensor Circuit No Activity Bank 1 Sensor 1
P0134 means the upstream oxygen sensor signal on bank 1 shows little or no activity.
What it means
The computer is not seeing the oxygen sensor switch as expected during operation.
Common symptoms
- Check engine light
- Poor fuel economy
- Rough idle in some cases
- Emissions failure
- Usually drivable
Likely causes
- Failed oxygen sensor
- Open signal circuit
- Connector issue
- Exhaust leak
- Sensor heater or ground problem
First checks
- Inspect wiring and connector.
- Check for related heater codes.
- Confirm the engine reaches closed loop.
- Do not confuse sensor 1 with sensor 2.