What does code P0135 mean on a Mercury and is it safe to drive?
P0135: O2 Sensor Heater Circuit Malfunction (Bank 1, Sensor 1). Here's what it means on your Mercury, what usually causes it, what repairs typically cost, and how safe it is 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 for your Mercury
- 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 Mercury, repairs for P0135 often fall between $80 and $300, depending on the cause and whether you use OEM or aftermarket parts. Labor rates vary by location.