P164B Mercury Code - O2 Sensor Positive Current Trim Circuit Performance Bank 2 Sensor 1

P164B indicates an issue with the O2 Sensor Positive Current Trim Circuit Performance for Bank 2 Sensor 1, meaning the sensor's current trim is out of its expected range.

Common symptoms include the check engine light turning on, poor fuel efficiency, rough idling, reduced engine performance, and elevated emissions.

Possible causes include a faulty Bank 2 Sensor 1 oxygen sensor, damaged wiring or connectors in the sensor circuit, an exhaust leak, or a malfunctioning powertrain control module (PCM).

A technician will use a scan tool to confirm the code, inspect the wiring and connectors for damage, check for exhaust leaks, and test the oxygen sensor's operation.

While the vehicle may still be drivable, it is not recommended as it can lead to increased emissions, reduced fuel efficiency, and potential damage to the catalytic converter.

Repairs may include replacing the faulty oxygen sensor, repairing or replacing damaged wiring or connectors, fixing exhaust leaks, or reprogramming or replacing the PCM if needed.

Repair costs vary but typically range from $150 to $400, depending on whether the oxygen sensor needs replacement or if more extensive repairs are required.

Bank 2 refers to the side of the engine opposite Bank 1, and Sensor 1 is the upstream oxygen sensor located before the catalytic converter.

While unlikely, a severely clogged air filter can affect the air-fuel mixture and indirectly contribute to sensor performance issues. It’s worth checking during diagnostics.

Regular maintenance, such as inspecting the oxygen sensors, ensuring proper exhaust system function, and addressing engine issues promptly, can help prevent this code from recurring.