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

What does P0161 mean?

P0161 is a diagnostic trouble code indicating "O2 Sensor Heater Circuit Malfunction (Bank 2 Sensor 2)". A component in the o2 sensors has been flagged as malfunctioning by the vehicle's ECU. This requires diagnosis to determine whether the part itself has failed or if there is a related wiring or control issue.

Symptoms you may notice

• Check engine light (MIL) illuminated on dashboard
• Decreased fuel efficiency
• Rough or irregular idle
• Engine running rough
• Intermittent warning lights

Common causes

• Faulty o2 sensors component
• Wiring or connector issue in the related circuit
• Failed sensor providing incorrect readings
• Software/calibration issue requiring ECU update
• Related component causing secondary fault

What should you do?

This is a significant issue that should be diagnosed and repaired soon. Avoid long trips or heavy driving until the problem is resolved. Continued driving may cause additional damage.