P0155
O2 Sensor Heater Circuit Malfunction (Bank 2 Sensor 1)
This means the heater inside the oxygen sensor located before the catalytic converter on Bank 2 isn't working, preventing the sensor from reaching its operating temperature quickly.
The Powertrain Control Module (PCM) has detected a malfunction in the heater circuit of the upstream oxygen sensor on Bank 2.
Common causes
- high
Faulty O2 sensor (heater element failure)
The heater element within the O2 sensor is a common failure point due to heat cycles.
Typical part cost: $50-200 part
- medium
Wiring or connector issues to the O2 sensor
Damaged, corroded, or loose wires/connectors can interrupt the heater circuit.
Typical part cost: $0-50 (repair)
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First things to check
- 1Inspect O2 sensor wiring and connector for damage or corrosion
- 2Check resistance of the O2 sensor heater circuit (unplugged sensor)
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Related codes
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Frequently asked questions
What does 'Bank 2 Sensor 1' mean?
Bank 2 is the side of the engine that does NOT contain cylinder #1. Sensor 1 is the upstream oxygen sensor, located before the catalytic converter.
Is P0155 similar to P0135?
Yes, P0155 is essentially the same issue as P0135, but it occurs on Bank 2's upstream oxygen sensor instead of Bank 1's. The diagnostic steps are very similar.
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