HINT
- DTCs P2195 and P2196 indicate malfunctions related to the bank 1 air fuel ratio sensor circuit.
- DTCs P2197 and P2198 indicate malfunctions related to the bank 2 air fuel ratio sensor circuit.
- Bank 1 refers to the bank that includes cylinder No. 1.
- Bank 2 refers to the bank that does not include cylinder No. 1.
- When any of these DTCs are set, check the air fuel ratio sensor output voltage by entering the following menus: Powertrain /
Engine / Data List / A/F Control System / AFS Voltage B1S1 or AFS Voltage B2S1.
- Short-term fuel trim values can also be read using the Techstream.
- The ECM regulates the voltages at the A1A+, A2A+, A1A- and A2A- terminals of the ECM to a constant level. Therefore, the
air fuel ratio sensor output voltage cannot be confirmed without using the Techstream.
- If an air fuel ratio sensor malfunction is detected, the ECM sets a DTC.
MONITOR DESCRIPTION
- Sensor voltage detection monitor
- Under the air fuel ratio feedback control, if the air fuel ratio sensor output voltage indicates rich or lean for a certain period of time, the ECM
determines that there is a malfunction in the air fuel ratio sensor. The ECM illuminates the MIL and sets a DTC.
- Example:
- If the air fuel ratio sensor voltage output is less than 2.8 V (very rich condition) and heated oxygen sensor output voltage falls from 0.59 V
or more to less than 0.21 V for 5 seconds, the ECM sets DTC P2196 or P2198. Alternatively, if the air fuel ratio sensor voltage output is
more than 3.8 V (very lean condition) and heated oxygen sensor output voltage rises from less than 0.21 V to 0.59 V or more for 5
seconds, DTC P2195 or P2197 is set.
- Sensor current detection monitor
- A rich air fuel mixture causes a low air fuel ratio sensor current, and a lean air fuel mixture causes a high air fuel ratio sensor current.
Therefore, the sensor output becomes low during acceleration, and it becomes high during deceleration with the throttle valve fully closed.
The ECM monitors the air fuel ratio sensor current during fuel cut and detects any abnormal current values.
- If the air fuel ratio sensor output is 3.6 mA or more for more than 3 seconds of cumulative time, the ECM interprets this as a malfunction
in the air fuel ratio sensor and sets DTC P2195 or P2197 (high-side stuck). If the air fuel ratio sensor output is 1.0 mA or less for more
than 3 seconds of cumulative time, the ECM sets DTC P2196 or P2198 (low-side stuck).
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