P0161 - O2 Sensor Heater Circuit Malfunction (Bank 2 Sensor 2)

An oxygen sensor circuit issue was detected.

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Code Overview

An oxygen sensor circuit issue was detected.

Common Causes

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

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