P0134 — O2 Sensor Circuit No Activity Detected (Bank 1 Sensor 1)
Category: Powertrain Severity: Medium
Updated:
DTC code P0134 means: O2 Sensor Circuit No Activity Detected (Bank 1 Sensor 1). It falls under the "Powertrain" category, with an estimated severity of Medium. Common causes include worn-out O2 sensor, failed sensor heater and broken signal wire; it's worth confirming the diagnosis before replacing parts.
Possible causes
- Worn-out O2 sensor
- Failed sensor heater
- Broken signal wire
- Disconnected connector
Symptoms
- Check engine light
- Higher fuel consumption
- Mild hesitation
How to diagnose it step by step
- Watch the sensor signal when warm.
- Check the heater (related P0030/P0135).
- Check the wiring.
- Replace the sensor.
How to fix it
A flat signal around 0.45 V means a dead sensor or open circuit. Check the connector and, if it's fine, replace the sensor.
Estimated repair cost
$100–300.
Frequently asked questions
What does DTC code P0134 mean?
O2 Sensor Circuit No Activity Detected (Bank 1 Sensor 1).
Is code P0134 serious?
Severity Medium. Not urgent, but worth diagnosing to avoid bigger damage.
Can I keep driving with code P0134?
Yes, it is safe to drive.
Related codes
P0133 P0135 P0132 P0136 P0131 P0137 P0130 P0138 P0139 P0128
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