Check Engine Codes / P0135
P0135 Code
O2 Sensor Heater Circuit Malfunction (Bank 1, Sensor 1)
What it means
The heater inside the upstream oxygen sensor failed — the sensor works but takes far longer to start reporting, hurting cold-start fuel trim.
Can you keep driving?
Yes.
Common causes
Listed most-common first. Fix cost depends on which one it turns out to be — check your quote free below.
⚠️ Don't get ripped off
Straightforward sensor swap on most cars — well under an hour of labor. A steep quote for a single non-buried O2 sensor deserves a second look.
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Related codes
Informational only — codes share symptoms across vehicles, so proper diagnosis on your specific car always comes first.