Trouble Code P2196: O2 Sensor Signal Stuck Rich (Bank 1 Sensor 1)

Engine Code P2196

Trouble code P2196 means “O2 Sensor Signal Stuck Rich (Bank 1 Sensor 1).” This pertains to the oxygen sensor in the exhaust system of a vehicle. When the internal combustion engine goes through its combustion process and ignites the air and fuel mixture in its cylinders, it produces exhaust fumes that contain toxins and some traces of oxygen.

The Exhaust Fumes

The exhaust fumes pass through a catalytic converter, which is a device that reduces the number of pollutants and toxins in the fumes. But first, the oxygen sensor detects the level of unburned oxygen that exists in the fumes. It is important for the engine control unit to know the level of unburned oxygen in the fumes because it determines whether the air to fuel ratio in the engine cylinders is rich or lean.

A Rich Air-to-fuel Ratio

A rich air-to-fuel ratio means you have more fuel and less oxygen, while a lean air-to-fuel ratio means you have more oxygen and less fuel. The engine control unit compares this information to the outside air in order to manage the air and fuel requirements of the engine. Trouble code P2196 means you have more fuel than oxygen in the air-to-fuel ratio. It could also mean Oxygen Sensor 1 in Bank 1 is malfunctioning and providing bad ratio information to the engine control unit.

Some of the symptoms you’ll notice of trouble code P2196 include weak engine performance, bad fuel economy, Check Engine warning light turning on and lots of smokiness coming out of the exhaust pipe. These symptoms happen whenever you have more fuel burning than air in the cylinders.

Malfunction of Oxygen Sensor 1 Bank 1

A malfunction of Oxygen Sensor 1 Bank 1 is the common reason for the problem. But there could also be other reasons for the problem too, such as a vacuum leak, exhaust leak, dirty mass airflow, bad oxygen sensor wiring, leaky fuel injector, high fuel pressure, and a bad engine control unit.

Due to the severity of these symptoms, you cannot leave this problem alone for very long. It is in your best interest to have a mechanic discover the cause and fix it as soon as possible. Otherwise, the problem could end up damaging your catalytic converter and valves.


Trouble code P2196 refers to an oxygen sensor in the exhaust system, causing a rich air-to-fuel ratio in the engine. This can result in weak engine performance, poor fuel economy, and smokiness. The oxygen sensor may be malfunctioning, and other issues may also be at play. It is crucial to have a mechanic diagnose and fix the issue as soon as possible to avoid damaging the catalytic converter and valves.

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