P0155 — 02 Sensor Heater Circuit Malfunction (Bank 2 Sensor 1)
Category: Powertrain Severity: Medium
Updated:
DTC code P0155 means: 02 Sensor Heater Circuit Malfunction (Bank 2 Sensor 1). It falls under the "Powertrain" category, with an estimated severity of Medium. Common causes include faulty oxygen (O2) sensor (Bank 2 Sensor 1), wiring or connector damage/corrosion and exhaust leak near the sensor; it's worth confirming the diagnosis before replacing parts.
Possible causes
- Faulty oxygen (O2) sensor (Bank 2 Sensor 1)
- Wiring or connector damage/corrosion
- Exhaust leak near the sensor
- Blown fuse (if heater-related)
Symptoms
- Check engine light on
- Increased fuel consumption
- Rough idle in some cases
- Possible failed emissions test
How to diagnose it step by step
- Check the heater fuse.
- Measure heater resistance (bank 2, sensor 1).
- Check supply.
- Replace the sensor.
How to fix it
Inspect the wiring and connector of the Bank 2 Sensor 1 oxygen sensor for damage or corrosion, and check for exhaust leaks nearby. If both are fine, the sensor itself is most likely faulty and should be replaced — O2 sensors wear out over time and don't have a simple repair.
Estimated repair cost
$100–300.
Frequently asked questions
What does DTC code P0155 mean?
02 Sensor Heater Circuit Malfunction (Bank 2 Sensor 1).
Is code P0155 serious?
Severity Medium. Not urgent, but worth diagnosing to avoid bigger damage.
Can I keep driving with code P0155?
Yes, it is safe to drive.
Related codes
P0156 P0153 P0157 P0151 P0150 P0161 P0141 P0140 P0139 P0171
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