2008 Subaru P0135: What It Means & Is It Safe to Drive?

P0135 on the 2008 Subaru: O2 Sensor Heater Circuit Malfunction (Bank 1, Sensor 1). Here's what it means, what usually causes it, what repairs typically cost, and whether it's safe to keep driving.

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What this code means

The heater circuit for the upstream O2 sensor on bank 1 has a fault. Sensor may still work but take longer to go closed-loop.

Common causes on the 2008 Subaru

  • Failed O2 sensor (heater element)
  • Open or short in heater wiring

Symptoms

  • Check Engine Light
  • Possible slightly worse fuel economy

Typical fixes

  • Replace bank 1 sensor 1 O2 sensor
  • Repair wiring

Repair cost range

For a 2008 Subaru, repairs for P0135 typically fall between $80 and $300, depending on the root cause and labor rates in your area.

Is it safe to keep driving your 2008 Subaru with this code?

For driving-safety guidance—how far you can go, when to tow, and what's urgent—see these checklists:

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