P0155: O2 sensor heater circuit malfunction (Bank 2 Sensor 1)
Drive carefully. Get it checked within a week or two.
Can I drive with P0155?
Yes, but drive carefully and get it checked soon. A sensor that helps set the fuel mixture is not warming up properly. The car usually runs, but fuel economy and emissions can get worse.
What does P0155 mean?
P0155 stands for O2 Sensor Heater Circuit Malfunction (Bank 2, Sensor 1).
Symptoms you may notice
- Check engine light illuminated
- Slightly increased tailpipe emissions during the first 3 minutes of warm-up
- Normal engine performance once warmed up
How much does it cost to fix?
Repair costs for code P0155 depend on the specific underlying root cause, ranging from simple DIY checks to component replacement. The table below lists the most common causes and rough price ranges in USD:
- Burned out heater element in Bank 2 sensor
- Blown O2 heater fuse
- Corroded connector terminals
- Damaged wiring near exhaust manifold
What to do next
- Check the engine compartment fuse box for blown heater fuses.
- Measure heater coil resistance on the Bank 2 sensor connector.
- Replace Bank 2 Sensor 1 oxygen sensor.
Last updated: October 2026
Related codes
General guidance only, not a professional diagnosis. If the check-engine light is flashing, or the car is running rough, overheating or losing power, stop driving and get help.
About this code
Code P0155 applies only to the electric warm-up heater in the front Bank 2 oxygen sensor. Safe to drive for a short time, but get it checked.