P2195 Oxygen (A/F) Sensor Signal Stuck Lean (Bank 1 Sensor 1)
DESCRIPTION
The Air-fuel Ratio (A/F) sensor generates voltage* in response to the actual air-fuel ratio. This sensor output voltage provide feedback to the ECM. The ECM uses the feedback to control the air-fuel ratio. Using the sensor output voltage, the ECM determines the deviation from the stoichiometric air-fuel ratio, and regulates the injection time. If the A/F sensor is malfunctioning, the ECM is unable to control the air-fuel ratio accurately.
The A/F sensor is equipped with a heater which heats the zirconia element. The heater is also controlled by the ECM. When the intake air volume is low (the temperature of the exhaust gas is low), a current flows to the heater to heat the sensor to facilitate the detection of accurate oxygen concentration.
The A/F sensor is a planar type. Compared to the conventional type, the sensor and heater portions are narrower. The heat of the heater is conducted to the zirconia element through the alumina, accelerating sensor activation.
To obtain a high purification rate of carbon monoxide (CO), hydrocarbon (HC) and nitrogen oxide (NOx) in the exhaust gas, a Three-Way Catalytic Converter (TWC) is used. The TWC is most efficient when the air-fuel ratio is maintained near the stoichiometric air-fuel ratio.
Trouble Area
- Open or short in A/F sensor (bank 1, 2 sensor 1) circuit
- A/F sensor (bank 1, 2 sensor 1)
- A/F sensor (bank 1, 2 sensor 1) heater
- A/F relay
- A/F sensor heater and relay circuits
- Air induction system
- Fuel pressure
- Injector
- ECM