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Oxygen sensor heater

P0135
Oxygen Sensor Heater Circuit (Bank 1 Sensor 1)

The small heater inside an oxygen sensor isn't working. The heater gets the sensor up to temperature quickly after a cold start.

Fine to drive

Can I keep driving? Yes, in most cases. It won't hurt the car in the short term, but get it fixed. A check engine light that's already on can't warn you about a new problem. The car drives normally. Fuel economy and emissions are a little worse until the engine warms up, and it will fail an emissions test.

What the words mean

  • Bank 1 is the side of the engine with cylinder 1. A four-cylinder engine has only one bank.
  • Sensor 1 is the oxygen sensor before the catalytic converter.

Common causes

  • The sensor's heater has burned out (the usual cause on an older sensor)
  • A blown fuse for the heater circuit
  • Damaged wiring or a corroded connector near the exhaust

Listed roughly from most to least likely. The same code can have different causes on different cars.

What to do

  1. Check the fuse for the oxygen sensor heaters.
  2. Look at the wiring near the exhaust for melted or rubbed-through spots.
  3. Replace the sensor named in the code if the wiring is sound.

General guidance. Your owner's manual wins. If a red warning light is on or the car drives differently, stop safely and get help.

Related codes

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