SVCS
P0135

O2 Sensor Heater Circuit (Bank 1, Sensor 1)

Medium — service soonPowertrain (engine & transmission)
System
Powertrain (engine & transmission)
Type
Generic (standardized)
Subsystem
Fuel & air metering

What it means

The heater element inside the upstream oxygen sensor (bank 1) is not working, so the sensor warms up too slowly.

Symptoms

Check-engine light, possibly worse cold-start emissions and economy.

Common causes

Failed sensor heater, blown fuse, or wiring/connector fault.

Recommended action

Check the heater fuse and circuit; usually the oxygen sensor needs replacing.

Related codes

P0300Random/Multiple Cylinder Misfire DetectedP0301Cylinder 1 Misfire DetectedP0302Cylinder 2 Misfire DetectedP0303Cylinder 3 Misfire DetectedP0304Cylinder 4 Misfire DetectedP0420Catalyst System Efficiency Below Threshold (Bank 1)P0430Catalyst System Efficiency Below Threshold (Bank 2)P0171System Too Lean (Bank 1)P0174System Too Lean (Bank 2)P0172System Too Rich (Bank 1)P0175System Too Rich (Bank 2)P0101Mass Air Flow (MAF) Circuit Range/Performance

FAQ — P0135

What does code P0135 mean?

O2 Sensor Heater Circuit (Bank 1, Sensor 1). The heater element inside the upstream oxygen sensor (bank 1) is not working, so the sensor warms up too slowly.

What are the symptoms of P0135?

Check-engine light, possibly worse cold-start emissions and economy.

What causes P0135?

Failed sensor heater, blown fuse, or wiring/connector fault.

What should I do about P0135?

Check the heater fuse and circuit; usually the oxygen sensor needs replacing.

General reference based on the SAE J2012 standard. Exact causes for your vehicle may differ — when in doubt, consult a workshop.

← All OBD-II codes