What P0161 means
02 Sensor Heater Circuit Malfunction (Bank 2 Sensor 2)
Common causes (general)
Before spending money on parts, verify the code with a scan tool and read freeze frame data. Freeze frame captures every sensor value at the moment the code set — this is often enough to figure out the root cause without further testing.
Manufacturer-specific descriptions
Different manufacturers use this code for slightly different failure modes. Here's what your specific make means by P0161:
| BMW | O2 Sensor Heater Circuit |
| FORD | Heated O2 Sensor Heater Circuit Malfunction (Bank 2, Sensor 2) |
| HONDA | Front Secondary Heated Oxygen Sensor (Secondary HO2S) (Bank 2, Sensor 2) Heater Circuit Malfunction |
| MITSUBISHI | O2 Sensor Heater Circuit Malfunction (Bank 2 Sensor 2); Oxygen sensor2(rear) heater |
| NISSAN | O2 Sensor Heater Circuit Malfunction (Bank 2 Sensor 2) |
| VOLKSWAGEN | HO2S Heater Performance Bank 2 Sensor 2 |
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