MasterTuning Fault code dictionary (DTC)

P0155 — Oxygen Sensor Heater Circuit Malfunction

Severity: Warning Can you drive? Yes, no known limitation Make: All makes (OBD-II standard)
MeaningThe engine computer has detected a problem with the internal heating circuit of the oxygen sensor located on Bank 2, Sensor 1. This heater helps the sensor reach its correct operating temperature quickly after you start the car so it can properly read the exhaust gases.
FamilyPowertrain (P)

Typical symptoms

Check Engine light is on
Increased fuel consumption over time
Rough engine running when the engine is cold

Common causes

Faulty oxygen sensor internal heater
Blown fuse related to the oxygen sensor heater circuit
Damaged wiring or loose connector at the sensor

What to do

Check the wiring harness and fuses linked to the oxygen sensor first, as these are quick to inspect. Plan to have the sensor tested soon, since a cold sensor delays proper fuel adjustment.

Frequently asked questions

What does code P0155 mean?

Oxygen Sensor Heater Circuit Malfunction. The engine computer has detected a problem with the internal heating circuit of the oxygen sensor located on Bank 2, Sensor 1. This heater helps the sensor reach its correct operating temperature quickly after you start the car so it can properly read the exhaust gases.

Can I keep driving with code P0155 active?

Yes, no known limitation

Common causes — P0155

Faulty oxygen sensor internal heater Blown fuse related to the oxygen sensor heater circuit Damaged wiring or loose connector at the sensor

How do you fix code P0155?

Check the wiring harness and fuses linked to the oxygen sensor first, as these are quick to inspect. Plan to have the sensor tested soon, since a cold sensor delays proper fuel adjustment.

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