P0135 Code: O2 Sensor Heater Circuit (Bank 1 Sensor 1)
P0135 means the heater circuit inside the upstream O2 sensor (bank 1) is faulty.
- Applies to
- All OBD-II vehicles (any make or model)
- Est. repair cost
- $60 – $350
- Time to fix
- 1-3 hours
What it means
Common causes are a failed heater element in the O2 sensor, a blown fuse, or wiring/connector faults. This is a generic OBD-II powertrain code defined in the SAE J2012 standard, so it applies to virtually any 1996-or-newer OBD-II vehicle — cars, trucks, and modern fuel-injected motorcycles — from any manufacturer (Toyota, Honda, Ford and the rest). Read it with any OBD-II scanner; the meaning is the same across brands, though the exact repair can vary by engine.
Symptoms
- Check engine light on
- Slower closed-loop fuelling when cold
- Possible economy drop
How to fix it
- 1
Check the fuse and O2 heater
1. Check the O2 heater fuse and wiring. 2. Test the sensor’s heater resistance. 3. Replace the O2 sensor if the heater is open, then clear the code.
Frequently asked questions
Can I drive with P0135?
Usually yes for a while — the sensor still works once warm — but it delays closed-loop and can hurt economy. Replace the sensor when convenient.
Last updated July 16, 2026
Guidance only — always consult a qualified professional or the official service manual before carrying out repairs.