Check Engine Code
P0135
O2 Sensor Heater Circuit Malfunction (Bank 1, Sensor 1)
What P0135 means
Modern O2 sensors include an internal heater so they reach operating temperature faster after a cold start. P0135 means the heater circuit is open, shorted, or drawing too little current — typically a failed sensor.
Vehicle-specific P0135 guides
P0135 can mean different things on different vehicles. Pick your make for engine-family specifics:
Symptoms
- Check engine light
- Slower warm-up period where the car runs in open loop longer
- Slight fuel economy hit on short trips
Likely causes (most common first)
- Failed O2 sensor heater element (most common)
- Blown fuse for the O2 heater circuit
- Broken or corroded connector at the sensor
- Wiring fault between the sensor and the ECM
Can I keep driving?
Low — mostly emissions/economy
Typical repair cost
DIY fixes can start near $40 (parts only). Shop repairs for P0135 typically run up to $300 depending on the underlying cause and vehicle. Start with the most common cause — Failed O2 sensor heater element (most common) — before throwing parts at it.
Symptoms that match P0135
If you got here from a search query, one of these might describe what your car is actually doing:
Related codes
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