A burned-out heater in the oxygen sensor (most common). A blown fuse. An open wire or corroded connector.

P0031 HO2S Heater Control Circuit Low (Bank 1 Sensor 1)

Q: What does P0031 mean?

P0031 means the heater circuit of bank 1's front oxygen sensor reads low, usually because the sensor's heater has burned out. The heater circuit for the front oxygen sensor on bank 1 is reading low, usually because the heater element is open or the circuit has lost power.

Oxygen sensors

P0031 means the heater circuit of bank 1's front oxygen sensor reads low, usually because the sensor's heater has burned out.

The heater circuit for the front oxygen sensor on bank 1 is reading low, usually because the heater element is open or the circuit has lost power.

Can I keep driving? Yes, for now.

Safe to drive. Fuel control may be a little off right after cold starts.

Common causes

A burned-out heater in the oxygen sensor (most common)
A blown fuse
An open wire or corroded connector

Symptoms

Check-engine light
Slightly worse fuel economy

What to check first

Check the heater fuse.
Measure heater resistance at the sensor (an open circuit means the sensor's heater is gone).
Inspect the wiring near the exhaust.
Replace the sensor if the heater is open.

What does P0031 mean on your vehicle?

The likely cause depends on your engine. iRepair researches your exact year, make, model and engine (service bulletins, recalls and owner reports) and tells you what to check first. Your first 3 questions are free.

Ask iRepair about P0031

No scanner? Most auto parts stores read check-engine codes for free.

Related codes

General guidance for P0031 on most vehicles. Some makers use the same code a little differently; confirm in the service information for your vehicle, put safety first, and see a professional when in doubt.