P0155 - O2 Sensor Heater Circuit Malfunction (Bank 2 Sensor 1)

An oxygen sensor circuit issue was detected.

Code Overview

An oxygen sensor circuit issue was detected.

Common Causes

• Failed heater element in bank 2 sensor 1
• Open or short in the heater wiring
• Blown fuse or missing heater power supply
• Loose or corroded connector at the sensor

Symptoms

• Check-engine light with little immediate drivability change
• Oxygen-sensor monitor may run slowly
• Failed emissions readiness or inspection

Diagnostic Steps

1. Inspect the bank 2 sensor 1 connector and wiring near the exhaust
2. Verify heater-circuit power, ground, and fuse protection
3. Check heater resistance if service information supports it
4. Confirm the heater fault before replacing the sensor

Repair Difficulty

Moderate

General difficulty estimate for the most common repair path.

Likely Repairs & Cost Guides

Use test results to confirm the fault before pricing the repair.

Related OBD Codes

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Next Steps

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