SFI SYSTEM, Diagnostic DTC:P2195, P2196

DTC Code DTC Name
P2195 Oxygen (A/F) Sensor Signal Stuck Lean (Bank 1 Sensor 1)
P2196 Oxygen (A/F) Sensor Signal Stuck Rich (Bank 1 Sensor 1)

DESCRIPTION

Tech Tips


  • 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 catalyst 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 time. If the air fuel ratio sensor malfunctions, the ECM is unable to control the air fuel ratio accurately.

The air fuel ratio sensor is of the planar type and is integrated with the 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), a current flows into the heater to heat the sensor in order to facilitate accurate air-fuel ratio detection. The heat generated by the heater is conducted to the solid electrolyte through the alumina, therefore the sensor activation is accelerated.

A three way catalytic converter is used in order to convert the carbon monoxide, hydrocarbons, and nitrogen oxide into less harmful substances. To allow the three way catalyst converter to function effectively, it is necessary to keep the air fuel ratio of the engine near the stoichiometric air fuel ratio.

*: Value changes inside the ECM. Since the air fuel ratio sensor is the current output element, a 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.

A0056UYE01
DTC No. DTC Detection Condition Trouble Area
P2195

Conditions (a) and (b) continue for 10 seconds or more

(2 trip detection logic):

(a) Air fuel ratio sensor voltage more than 3.8 V

(b) Heated oxygen sensor voltage 0.15 V or more


  • Open or short in air fuel ratio sensor (sensor 1) circuit

  • Air fuel ratio sensor (sensor 1)

  • Air fuel ratio sensor heater (sensor 1)

  • Integration relay (EFI MAIN relay)

  • Air fuel ratio sensor heater circuit

  • ECM

While fuel-cut operation is performed (during vehicle deceleration), air fuel ratio sensor current 3.6 mA or more for 3 seconds (2 trip detection logic)
  • Air fuel ratio sensor (sensor 1)

  • ECM

P2196

Conditions (a) and (b) continue for 10 seconds or more

(2 trip detection logic):

(a) Air fuel ratio sensor voltage less than 2.8 V for 10 seconds

(b) Heated oxygen sensor voltage less than 0.6 V


  • Open or short in air fuel ratio sensor (sensor 1) circuit

  • Air fuel ratio sensor (sensor 1)

  • Air fuel ratio sensor heater (sensor 1)

  • Integration relay (EFI MAIN relay)

  • Air fuel ratio sensor heater circuit

  • ECM

While fuel-cut operation is performed (during vehicle deceleration), air fuel ratio sensor current less than 1.0 mA for 3 seconds (2 trip detection logic)
  • Air fuel ratio sensor (sensor 1)

  • ECM

Tech Tips


  • When either of these DTCs is output, check the air fuel ratio sensor output voltage by entering the following menus on the intelligent tester: Powertrain / Engine and ECT / Data List / AFS Voltage B1S1.

  • Short-term fuel trim values can also be read using the intelligent tester.

  • The ECM regulates the voltages at the A1A+ and A1A- terminals of the ECM to a constant level. Therefore, the air fuel ratio sensor output voltage cannot be confirmed without using the intelligent tester.

  • If the air fuel ratio sensor is malfunctioning, the ECM sets the DTC P2195 or P2196.

WIRING DIAGRAM

A0057WLE09

CONFIRMATION DRIVING PATTERN


CAUTION / NOTICE / HINT

Tech Tips

Malfunctioning areas can be identified by performing the "Control the Injection Volume for A/F Sensor" function provided in the Active Test. The "Control the Injection Volume for A/F Sensor" function can help determine whether the air fuel ratio sensor, heated oxygen sensor and other potential trouble areas are malfunctioning.

The following instructions describe how to conduct the "Control the Injection Volume for A/F Sensor" operation using the intelligent tester.


  1. Connect the intelligent tester to the DLC3.

  2. Start the engine.

  3. Turn the tester on.

  4. Warm up the engine at an engine speed of 2500 rpm for approximately 90 seconds.

  5. On the tester, enter the following menus: Powertrain / Engine and ECT / Active Test / Control the Injection Volume for A/F Sensor.

  6. Perform the "Control the Injection Volume for A/F Sensor" operation with the engine idling (press the RIGHT or LEFT button to change the fuel injection volume).

  7. Monitor the output voltages of the air fuel ratio and heated oxygen sensors (AFS Voltage B1S1 and O2S B1S2) displayed on the tester.

Tech Tips


  • The "Control the Injection Volume for A/F Sensor" operation lowers the fuel injection volume by 12.5% or increases the injection volume by 12.5%.

  • The sensors react in accordance with increases and decreases in the fuel injection volume.

Standard

Tester Display

(Sensor)

Injection Volume Status Voltage

AFS Voltage B1S1

(A/F)

+12.5% Rich Below 3.1
-12.5% Lean Higher than 3.4

O2S B1S2

(HO2)

+12.5% Rich Higher than 0.55
-12.5% Lean Below 0.4

Note

The air fuel ratio sensor has an output delay of a few seconds and the heated oxygen sensor (sensor 2) output has a maximum output delay of approximately of 20 seconds.

A0056SUE19

Tech Tips


  • DTC P2A00 may be set when the air fuel ratio is stuck rich or lean.

  • Read freeze frame data using the intelligent tester. The ECM records vehicle and driving condition information as freeze frame data the moment a DTC is stored. When troubleshooting, freeze frame data can help determine if the vehicle was moving or stationary, if the engine was warmed up or not, if the air fuel ratio was lean or rich, and other data from the time the malfunction occurred.

  • A low air fuel ratio sensor voltage could be caused by a rich air-fuel mixture. Check for conditions that would cause the engine to run rich.

  • A high air fuel ratio sensor voltage could be caused by a lean air-fuel mixture. Check for conditions that would cause the engine to run lean.

Note

Inspect the fuses for circuits related to this system before performing the following inspection procedure.

PROCEDURE


  1. CHECK ANY OTHER DTCS OUTPUT (IN ADDITION TO P2195 OR P2196)


    1. Connect the intelligent tester to the DLC3.

    2. Turn the ignition switch to ON.

    3. Turn the tester on.

    4. Enter the following menus: Powertrain / Engine and ECT / DTC.

    5. Read the DTCs.

      Result
      Display (DTC Output) Proceed to
      P2195 or P2196 A
      P2195 or P2196 and P0136, P0137 or P0138
      P2195 or P2196 and other DTCs B

      Tech Tips

      If any DTCs relating to the air fuel ratio sensor (DTCs for the air fuel ratio sensor heater or air fuel ratio sensor admittance) are output, troubleshoot those DTCs first.


    B
    A
  2. CONFIRM IF VEHICLE HAS RUN OUT OF FUEL IN PAST


    1. Has the vehicle run out of fuel in the past?


    YES
    NO
  3. READ VALUE USING INTELLIGENT TESTER (TEST VALUE OF AIR FUEL RATIO SENSOR)


    1. Connect the intelligent tester to the DLC3.

    2. Turn the ignition switch to ON.

    3. Turn the tester on.

    4. Clear the DTCs Click here.

    5. Drive the vehicle in accordance with the drive pattern described in the CONFIRMATION DRIVING PATTERN.

    6. Enter the following menus: Powertrain / Engine and ECT / Utility / Monitor Status.

    7. Check that the status of "O2 Sensor" is "Complete".

      If the status is still "Incomplete", drive the vehicle according to the driving pattern again.

      Tech Tips


      • "Available" indicates that the component has not been monitored yet.

      • "Complete" indicates that the component is functioning normally.

      • "Incomplete" indicates that the component is malfunctioning.

    8. Enter the following menus: Powertrain / Engine and ECT / Data List / AFS Current B1S1.

    9. Check the test value of the air fuel ratio sensor output current during fuel-cut (Refer to the Monitor Driving Pattern 2 [Detail for Procedure "C" through Procedure "F"] in the CONFIRMATION DRIVING PATTERN).

      Result
      Test Value Proceed to
      Within normal range (1.0 mA or more, and less than 3.6 mA) A
      Outside normal range (Less than 1.0 mA, or 3.6 mA or more) B

    B
    A
  4. READ VALUE USING INTELLIGENT TESTER (OUTPUT VOLTAGE OF AIR FUEL RATIO SENSOR)


    1. Connect the intelligent tester to the DLC3.

    2. Start the engine.

    3. Turn the tester on.

    4. Warm up the air fuel ratio sensor at an engine speed of 2500 rpm for 90 seconds.

    5. On the tester, enter the following menus: Powertrain / Engine and ECT / Data List / AFS Voltage B1S1 and Engine Speed / Function / Snap Shot Record.

    6. Check the air fuel ratio sensor voltage 3 times, when the engine is in each of the following conditions:


      1. While idling (for at least 30 seconds) (Step "A").

      2. At an engine speed of approximately 2500 rpm (without any sudden changes in engine speed) (Step "B").

      3. Raise the engine speed to 4000 rpm and then quickly release the accelerator pedal so that the throttle valve is fully closed (Step "C").

        Standard Voltage
        Condition A/F Sensor Voltage Variation Reference
        Step "A" and Step "B" Remains at approximately 3.25 V Between 3.1 V and 3.4 V
        Step "C" Increases to 3.8 V or more

        This occurs during engine deceleration

        (when fuel-cut performed)

      Tech Tips


      • For more information, see the diagrams below.

        A00535KE03
      • If the output voltage of the air fuel ratio sensor remains at approximately 3.25 V (see Malfunction Condition diagram) under any conditions, including those above, the air fuel ratio sensor may have an open circuit. (This will also happen if the air fuel ratio sensor heater has an open circuit.)

      • If the output voltage of the air fuel ratio sensor remains at either approximately 3.8 V or more, or 2.8 V or less (see Malfunction Condition diagram) under any conditions, including those above, the air fuel ratio sensor may have a short circuit.

      • The ECM stops fuel injection (fuel cut) during engine deceleration. This causes a lean condition and results in a momentary increase in the air fuel ratio sensor output voltage.

      • The ECM must establish a closed throttle valve position learning value to perform fuel cut. If the battery terminal has been reconnected, the vehicle must be driven over 16 km/h (10 mph) to allow the ECM to learn the closed throttle valve position.

      • When the vehicle is driven:

        The output voltage of the air fuel ratio sensor may be below 2.8 V during fuel enrichment. For the vehicle, this translates to a sudden increase in speed with the accelerator pedal fully depressed when trying to overtake another vehicle. The air fuel ratio sensor is functioning normally.

      • The air fuel ratio sensor is a current output element; therefore, the current is converted into a voltage inside the ECM. Measuring the voltage at the connectors of the air fuel ratio sensor or ECM will show a constant voltage result.


    NG
    OK
  5. REPLACE AIR FUEL RATIO SENSOR


    1. Replace the air fuel ratio sensor Click here.


    NEXT
  6. PERFORM CONFIRMATION DRIVING PATTERN


    NEXT
  7. CHECK WHETHER DTC OUTPUT RECURS (DTC P2195 OR P2196)


    1. Connect the intelligent tester to the DLC3.

    2. Turn the ignition switch to ON.

    3. Turn the tester on.

    4. Enter the following menus: Powertrain / Engine and ECT / DTC.

    5. Read the pending DTCs.

      Result
      Display (DTC Output) Proceed to
      No output A
      P2195 or P2196 B

    A
    B
  8. INSPECT AIR FUEL RATIO SENSOR (HEATER RESISTANCE)


    1. A00566YE31
      Text in Illustration
      *1

      Component without harness connected

      (Air Fuel Ratio Sensor)

      Disconnect the air fuel ratio sensor connector.

    2. Measure the resistance according to the value(s) in the table below.

      Standard Resistance
      Tester Connection Condition Specified Condition
      1 (HA1A) - 2 (+B) 20°C (68°F) 1.8 to 3.4 Ω
      1 (HA1A) - 4 (A1A-) Always 10 kΩ or higher
    3. Reconnect the air fuel ratio sensor.


    NG
    OK
  9. CHECK AIR FUEL RATIO SENSOR (POWER SOURCE)


    1. A0054R2E02
      Text in Illustration
      *1

      Front view of wire harness connector

      (to Air Fuel Ratio Sensor)

      Disconnect the air fuel ratio sensor connector.

    2. Turn the ignition switch to ON.

    3. Measure the voltage according to the value(s) in the table below.

      Standard Voltage
      Tester Connection Switch Condition Specified Condition
      B18-2 (+B) - Body ground Ignition switch ON 11 to 14 V
    4. Reconnect the air fuel ratio sensor connector.


    NG
    OK
  10. CHECK HARNESS AND CONNECTOR (AIR FUEL RATIO SENSOR - ECM)


    1. Disconnect the air fuel ratio sensor connector.

    2. Disconnect the ECM connector.

    3. Measure the resistance according to the value(s) in the table below.

      Standard Resistance (Check for open)
      Tester Connection Condition Specified Condition
      B18-1 (HA1A) - B39-104 (HA1A) Always Below 1 Ω
      B18-3 (A1A+) - B39-103 (A1A+) Always Below 1 Ω
      B18-4 (A1A-) - B39-126 (A1A-) Always Below 1 Ω
      Standard Resistance (Check for short)
      Tester Connection Condition Specified Condition
      B18-1 (HA1A) or B39-104 (HA1A) - Body ground Always 10 kΩ or higher
      B18-3 (A1A+) or B39-103 (A1A+) - Body ground Always 10 kΩ or higher
      B18-4 (A1A-) or B39-126 (A1A-) - Body ground Always 10 kΩ or higher
    4. Reconnect the ECM connector.

    5. Reconnect the air fuel ratio sensor connector.

      A005638E43

    NG
    OK
  11. CHECK INTAKE SYSTEM


    1. Check the intake system from vacuum leakage Click here.

      OK
      No leakage from intake system.

    NG
    OK
  12. CHECK FUEL PRESSURE


    1. Check the fuel pressure Click here.


    NG
    OK
  13. INSPECT INJECTOR ASSEMBLY


    1. Check the injector injection (whether fuel volume is high or low, and whether injection pattern is poor) Click here.


    NG
    OK
  14. REPLACE AIR FUEL RATIO SENSOR


    1. Replace the air fuel ratio sensor Click here.


    NEXT
  15. PERFORM CONFIRMATION DRIVING PATTERN


    NEXT
  16. CHECK WHETHER DTC OUTPUT RECURS (DTC P2195 OR P2196)


    1. Connect the intelligent tester to the DLC3.

    2. Turn the ignition switch to ON.

    3. Turn the tester on.

    4. Enter the following menus: Powertrain / Engine and ECT / DTC.

    5. Read the pending DTCs.

      Result
      Display (DTC Output) Proceed to
      No output A
      P2195 or P2196 B

    A
    B
  17. CHECK HARNESS AND CONNECTOR (AIR FUEL RATIO SENSOR - INTEGRATION RELAY)

    A00530IE01
    Text in Illustration
    *1

    Front view of wire harness connector

    (to Air Fuel Ratio Sensor)

    *2

    Front view of wire harness connector

    (to Integration Relay)


    1. Disconnect the air fuel ratio sensor connector.

    2. Remove the integration relay (EFI MAIN relay) from the engine room No. 1 relay block Click here.

    3. Disconnect the integration relay connector.

    4. Measure the resistance according to the value(s) in the table below.

      Standard Resistance (Check for open)
      Tester Connection Condition Specified Condition
      B18-2 (+B) - 1B-4 Always Below 1 Ω
      Standard Resistance (Check for short)
      Tester Connection Condition Specified Condition
      B18-2 (+B) or 1B-4 - Body ground Always 10 kΩ or higher
    5. Reconnect the air fuel ratio sensor connector.

    6. Reconnect the integration relay connector.

    7. Reinstall the integration relay.


    OK
    NG
  18. CHECK FUEL LINE


    1. Check the fuel lines for leaks or blockage Click here.


    OK
    NG