P0155

O2 Sensor Heater Circuit Malfunction (Bank 2, Sensor 1)

Severity: moderate Driveability: Safe To Drive AI generated

Plain-English meaning

The oxygen sensor heater circuit for the sensor located before the catalytic converter on bank 2 is not functioning properly.

What to check first

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What not to replace yet

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Stop driving when

You can continue driving cautiously; however, if you notice severe engine performance issues or warning lights indicating critical problems, seek professional assistance promptly.

Related symptoms

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Owner steps

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Likely causes

Faulty oxygen sensor heater element (medium)

Damaged or corroded wiring/connectors in the heater circuit (medium)

Blown fuse related to the oxygen sensor heater (medium)

Faulty powertrain control module (PCM) or engine control module (ECM) (medium)

Exhaust leaks near the sensor (medium)

Shop steps

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Follow-up questions

Has the vehicle recently undergone any exhaust or engine repairs?

Is the check engine light steady or flashing?

Are there any noticeable changes in engine performance or fuel economy?

Have you noticed any unusual smells or smoke from the exhaust?