DTC P2195 Oxygen (A/F) Sensor Signal Stuck Lean (Bank 1 Sensor 1); DTC P2196 Oxygen (A/F) Sensor Signal Stuck Rich (Bank 1 Sensor 1): Description
HINT:
- Although the DTC titles say oxygen sensor, these DTCs relate to the air-fuel ratio sensor.
- Sensor 1 refers to the sensor mounted in front of the three-way catalytic converter and located near the engine assembly.
The air fuel ratio sensor generates a voltage* that corresponds to the actual air-fuel ratio. This sensor voltage is used to provide the ECM with feedback so that it can control the air-fuel ratio. The ECM determines the deviation from the stoichiometric air-fuel ratio level, and regulates the fuel injection duration. If the air fuel ratio sensor malfunctions, the ECM is unable to control the air-fuel ratio accurately. The air fuel ratio sensor is a planar type with an integrated heater, which heats the solid electrolyte (zirconia element). This heater is controlled by the ECM. When the intake air volume is low (the exhaust gas temperature is low), current flows to the heater to heat the sensor, in order to facilitate accurate oxygen concentration detection. In addition, the sensor and heater portions are the narrow type. The heat generated by the heater is conducted to the solid electrolyte through the alumina, therefore the sensor activation is accelerated.
In order to obtain a high purification rate of the carbon monoxide (CO), hydrocarbon (HC) and nitrogen oxide (NOx) components in the exhaust gas, a three-way catalytic converter is used. For the most efficient use of the three-way catalytic converter, the air-fuel ratio must be precisely controlled so that it is always close to the stoichiometric level.
*: Value changes inside the ECM. Since the air fuel ratio sensor uses a current output element, the current is converted into a voltage inside the ECM. Any measurements taken at the air fuel ratio sensor or ECM connectors will show a constant voltage.
| DTC No. | DTC Detection Condition | Trouble Area |
|---|---|---|
| P2195 | Conditions (a) and (b) continue for 10 seconds or more (2 trip detection logic)
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| While fuel-cut operation performed (during vehicle deceleration), Air fuel ratio sensor current 3.6 mA or more for 3 seconds (2 trip detection logic) |
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| P2196 | Conditions (a) and (b) continue for 10 seconds or more (2 trip detection logic)
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| While fuel-cut operation performed (during vehicle deceleration), Air fuel ratio sensor current less than 1.0 mA for 3 seconds (2 trip detection logic) |
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HINT:
- When any of these DTCs are set, check the air fuel ratio sensor voltage output by entering the following menus: Powertrain / Engine and ECT / Data List / A/F Control System / AFS B1 S1.
- Short-term fuel trim values can also be read using the Techstream.
- The ECM regulates the voltages at the A1A+ and A1 A- terminals of the ECM to a constant level. Therefore, the air fuel ratio sensor voltage output cannot be confirmed without using the Techstream.
- If a air fuel ratio sensor malfunction is detected, the ECM sets a DTC.