SFI SYSTEM (w/o EGR 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

Although the DTC titles say oxygen sensor, these DTCs relate to the air fuel ratio sensor.

The air fuel ratio sensor generates 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 narrower than the conventional type. 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 (CO), hydrocarbon (HC), and nitrogen oxide (NOx) into less harmful substances. To allow the three-way catalytic 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 uses the current output element, the current is converted to a voltage inside the ECM. Any measurements taken at the air fuel ratio sensor or ECM connectors will show a constant voltage.

A003V43E01
DTC No. DTC Detection Condition Trouble Area
P2195

Conditions (a) and (b) continue for 5 seconds or more

(2 trip detection logic):

(a) Air fuel ratio sensor voltage is higher than 3.8 V.

(b) Heated oxygen sensor voltage is 0.21 V or higher.


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

  • Air fuel ratio sensor (sensor 1)

  • Intake system

  • Fuel pressure

  • Fuel injector assembly

  • ECM

While the fuel-cut operation is performed (during vehicle deceleration), the air fuel ratio sensor current is 2.2 mA or higher for 3 seconds (2 trip detection logic).
  • Air fuel ratio sensor (sensor 1)

  • ECM

P2196

Conditions (a) and (b) continue for 5 seconds or more

(2 trip detection logic):

(a) Air fuel ratio sensor voltage is below 2.8 V.

(b) Heated oxygen sensor voltage is below 0.59 V.


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

  • Air fuel ratio sensor (sensor 1)

  • Intake system

  • Fuel pressure

  • Fuel injector assembly

  • ECM

While the fuel-cut operation is performed (during vehicle deceleration), the air fuel ratio sensor current is below 0.7 mA for 3 seconds (2 trip detection logic).
  • Air fuel ratio sensor (sensor 1)

  • ECM

Tech Tips


  • When any of these DTCs are stored, check the air fuel ratio sensor output voltage by entering the following menus: Powertrain / Engine and ECT / Data List / All Data / 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 an air fuel ratio sensor malfunction is detected, the ECM stores a DTC.

MONITOR DESCRIPTION

Sensor voltage detection monitor

Under air-fuel ratio feedback control, if the air fuel ratio sensor output voltage is below 2.8 V (very rich condition) for 5 seconds despite the heated oxygen sensor output voltage being below 0.59 V, the ECM stores DTC P2196. Alternatively, if the air fuel ratio sensor output voltage is higher than 3.8 V (very lean condition) for 5 seconds despite the heated oxygen sensor output voltage being 0.21 V or higher, DTC P2195 is stored.

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 2.2 mA or higher for more than 3 seconds of cumulative time, the ECM interprets this as a malfunction in the air fuel ratio sensor and stores DTC P2195 (stuck on high side). If the air fuel ratio sensor output is below 0.7 mA for more than 3 seconds of cumulative time, the ECM stores DTC P2196 (stuck on low side).

A003Z79E20

MONITOR STRATEGY

Required Sensors/Components (Main) Air fuel ratio sensor
Required Sensors/Components (Related) Heated oxygen sensor
Frequency of Operation

Continuous: Sensor voltage detection monitor

Once per driving cycle: Sensor current detection monitor

Duration

5 seconds: Sensor voltage detection monitor

3 seconds: Sensor current detection monitor

TYPICAL ENABLING CONDITIONS

Sensor Voltage Detection Monitor
Time after engine start 30 seconds or more
Fuel system status Closed-loop
Sensor Current Detection Monitor
Auxiliary battery voltage 11 V or higher
Engine coolant temperature 75°C (167°F) or higher
Atmospheric pressure 76 kPa(abs) [570 mmHg(abs)] or higher
Air fuel ratio sensor status Activated
Continuous time of fuel cut 3 seconds or more, and less than 10 seconds

TYPICAL MALFUNCTION THRESHOLDS

P2195: Sensor Voltage Detection Monitor (Lean Side Malfunction)
Rear heated oxygen sensor voltage 0.21 V or higher
Air fuel ratio sensor voltage Higher than 3.8 V
P2196: Sensor Voltage Detection Monitor (Rich Side Malfunction)
Rear heated oxygen sensor voltage Below 0.59 V
Air fuel ratio sensor voltage Below 2.8 V
P2195: Sensor Current Detection Monitor (High Side Malfunction)
Air fuel ratio sensor current 2.2 mA or higher
P2196: Sensor Current Detection Monitor (Low Side Malfunction)
Air fuel ratio sensor current Below 0.7 mA

CONFIRMATION DRIVING PATTERN

A003XHCE70
A003ZV7E01

  1. Connect the intelligent tester to the DLC3.

  2. Turn the power switch on (IG).

  3. Turn the tester on.

  4. Clear the DTCs (even if no DTCs are stored, perform the clear DTC operation).

  5. Turn the power switch off and wait for at least 30 seconds.

  6. Turn the power switch on (IG) and turn the tester on.

  7. Put the engine in inspection mode (maintenance mode) Click here.

  8. Start the engine, and warm it up until the engine coolant temperature reaches 75°C (167°F) or higher [A].

  9. On the tester, enter the following menus to check the fuel-cut status: Powertrain / Engine and ECT / Data List / All Data / Idle Fuel Cut.

  10. Drive the vehicle at between 75 and 120 km/h (47 and 75 mph) for at least 10 minutes [B].

    CAUTION:

    When performing the confirmation driving pattern, obey all speed limits and traffic laws.

  11. Move the shift lever in B [C].

  12. Accelerate the vehicle to 75 km/h (47 mph) or more by depressing the accelerator pedal for at least 10 seconds [D].

  13. Soon after performing step [D] above, release the accelerator pedal for at least 4 seconds without depressing the brake pedal in order to execute fuel-cut control [E].

    Tech Tips

    While "Idle Fuel Cut" on the Data List is ON, fuel-cut control is being executed.

  14. Allow the vehicle to decelerate until the vehicle speed decreases to less than 10 km/h (6 mph).

  15. Repeat steps [C] through [E] above at least 3 times in one driving cycle.

  16. Enter the following menus: Powertrain / Engine and ECT / DTC [F].

  17. Read the pending DTCs.

    Tech Tips


    • If a pending DTC is output, the system is malfunctioning.

    • If a pending DTC is not output, perform the following procedure.

  18. Enter the following menus: Powertrain / Engine and ECT / Utility / All Readiness.

  19. Input the DTC: P2195 or P2196.

  20. Check the DTC judgment result.

    Tester Display Description
    NORMAL
    • DTC judgment completed

    • System normal

    ABNORMAL
    • DTC judgment completed

    • System abnormal

    INCOMPLETE
    • DTC judgment not completed

    • Perform driving pattern after confirming DTC enabling conditions

    N/A
    • Unable to perform DTC judgment

    • Number of DTCs which do not fulfill DTC preconditions has reached ECU memory limit

    Tech Tips


    • If the judgment result shows NORMAL, the system is normal.

    • If the judgment result shows ABNORMAL, the system has a malfunction.

    • If the judgment result shows INCOMPLETE or N/A, perform steps [B] through [F] again.

WIRING DIAGRAM

A003XPAE02

INSPECTION PROCEDURE

Note

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

Tech Tips


  • Sensor 1 refers to the sensor mounted in front of the three-way catalytic converter and located near the engine assembly.

  • 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.

  • Sensor 1 refers to the sensor closest to the engine assembly.

  • Sensor 2 refers to the sensor farthest away from the engine assembly.

PROCEDURE


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


    1. Connect the intelligent tester to the DLC3.

    2. Turn the power switch on (IG).

    3. Turn the tester on.

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

    5. Read the DTCs.

      Result
      Result Proceed to
      DTC P2195 or P2196 is output A
      DTC P2195 or P2196 and P0136, P0137 or P0138 are output A
      DTC P2195 or P2196 and other DTCs are output 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?


    NO
    YES
  3. PERFORM CONFIRMATION DRIVING PATTERN (DTC P2195 OR P2196)


    1. Connect the intelligent tester to the DLC3.

    2. Turn the power switch on (IG).

    3. Turn the tester on.

    4. Clear the DTCs Click here.

    5. Turn the power switch off and wait for at least 30 seconds.

    6. Turn the power switch on (IG) and turn the tester on.

    7. Put the engine in inspection mode (maintenance mode) Click here.

    8. Start the engine and warm it up.

    9. Drive the vehicle in accordance with the driving pattern described in the Confirmation Driving Pattern.

    10. Enter the following menus: Powertrain / Engine and ECT / Utility / All Readiness.

    11. Input the DTC: P2195 or P2196.

    12. Check the DTC judgment result.

      Result
      Result Proceed to
      NORMAL (DTC is not output) A
      ABNORMAL (DTC P2195 or P2196 is output) B

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


    1. Connect the intelligent tester to the DLC3.

    2. Turn the power switch on (IG).

    3. Turn the tester on.

    4. Clear the DTCs Click here.

    5. Put the engine in inspection mode (maintenance mode) Click here.

    6. Drive the vehicle in accordance with the driving pattern described in Confirmation Driving Pattern.

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

    8. Check the value of the air fuel ratio sensor output current during fuel-cut, referring to the Drive Pattern Detail for [C] through [F] in the Confirmation Driving Pattern.

      Tech Tips


      • To measure the air fuel ratio sensor current precisely, perform the fuel-cut operation as long as possible.

      • If it is difficult to measure the air fuel ratio sensor current, use the snapshot function of the tester.

      Result
      Test Value Proceed to
      Within normal range (0.7 mA or higher, and below 2.2 mA) A
      Outside normal range (below 0.7 mA, or 2.2 mA or higher) B

    B
    A
  5. PERFORM ACTIVE TEST USING INTELLIGENT TESTER (OUTPUT VOLTAGE OF AIR FUEL RATIO SENSOR)


    1. Connect the intelligent tester to the DLC3.

    2. Turn the power switch on (IG).

    3. Turn the tester on.

    4. Put the engine in inspection mode (maintenance mode) Click here.

    5. Start the engine.

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

      Tech Tips

      During charging control, the engine speed is set at idle. Therefore, the engine speed does not increase when depressing the accelerator pedal. In this case, warm up the engine after charging control has completed.

    7. Enter the following menus: Powertrain / Engine and ECT / Active Test / Control the Injection Volume for A/F Sensor / Data List / All Data / AFS Voltage B1S1 and O2S B1S2.

    8. Perform the Control the Injection Volume for A/F Sensor operation with the engine idling.

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

      • If the sensor output voltage does not change (almost no reaction) while performing the Active Test, the sensor may be malfunctioning.

      Standard
      Tester Display (Sensor) Injection Volume Status Voltage

      AFS Voltage B1S1

      (Air fuel ratio)

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

      O2S B1S2

      (Heated oxygen)

      12.5% Rich Higher than 0.55 V
      -12.5% Lean Below 0.4 V
      Result
      Status of AFS Voltage B1S1 Status of O2S B1S2 Air Fuel Ratio Condition and Air Fuel Ratio Sensor Condition Proceed to
      Lean Lean Actual air fuel ratio lean A
      Rich Rich Actual air fuel ratio rich A
      Lean Lean/Rich Air fuel ratio sensor malfunction B
      Rich Lean/Rich Air fuel ratio sensor malfunction B
      Lean/Rich Lean/Rich Normal B

      Lean: During the Control the Injection Volume for A/F Sensor Active Test, the air fuel ratio sensor output voltage (AFS Voltage B1S1) is consistently higher than 3.4 V, and the heated oxygen sensor output voltage (O2S B1S2) is consistently below 0.4 V.

      Rich: During the Control the Injection Volume for A/F Sensor Active Test, the AFS Voltage B1S1 is consistently below 3.1 V, and the O2S B1S2 is consistently higher than 0.55 V.

      Lean/Rich: During the Control the Injection Volume for A/F Sensor Active Test, the output voltage of the air fuel ratio sensor and heated oxygen sensor alternates correctly.

      Tech Tips

      Refer to "Data List / Active Test" [AFS Voltage B1S1 and O2S B1S2] Click here.


    B
    A
  6. CHECK INTAKE SYSTEM


    1. Check the intake system for vacuum leaks Click here.

      OK
      No leaks in intake system.

    NG
    OK
  7. CHECK FOR EXHAUST GAS LEAK


    1. Check for exhaust gas leaks.

      OK
      No gas leaks.

    NG
    OK
  8. CHECK FUEL PRESSURE


    1. Check the fuel pressure Click here.


    NG
    OK
  9. INSPECT FUEL INJECTOR ASSEMBLY


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


    NG
    OK
  10. REPLACE AIR FUEL RATIO SENSOR


    1. Replace the air fuel ratio sensor Click here.


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


    1. Connect the intelligent tester to the DLC3.

    2. Turn the power switch on (IG).

    3. Turn the tester on.

    4. Clear the DTCs Click here.

    5. Turn the power switch off and wait for at least 30 seconds.

    6. Drive the vehicle in accordance with the driving pattern described in the Confirmation Driving Pattern.

    7. Enter the following menus: Powertrain / Engine and ECT / Utility / All Readiness.

    8. Input the DTC: P2195 or P2196.

    9. Check the DTC judgment result.

      Result
      Result Proceed to
      ABNORMAL (DTC P2195 or P2196 is output) A
      NORMAL (DTC is not output) B

    B
    A
  12. REPLACE ECM


    1. Replace the ECM Click here.


    NEXT
  13. CONFIRM WHETHER MALFUNCTION HAS BEEN SUCCESSFULLY REPAIRED


    1. Connect the intelligent tester to the DLC3.

    2. Turn the power switch on (IG).

    3. Turn the tester on.

    4. Clear the DTCs Click here.

    5. Turn the power switch off and wait for at least 30 seconds.

    6. Drive the vehicle in accordance with the driving pattern described in the Confirmation Driving Pattern.

    7. Enter the following menus: Powertrain / Engine and ECT / Utility / All Readiness.

    8. Input the DTC: P2195 or P2196.

    9. Check the DTC judgment result.

      Result
      Tester Display Description
      NORMAL
      • DTC judgment completed

      • System normal

      ABNORMAL
      • DTC judgment completed

      • System abnormal

      INCOMPLETE
      • DTC judgment not completed

      • Perform driving pattern after confirming DTC enabling conditions

      N/A
      • Unable to perform DTC judgment

      • Number of DTCs which do not fulfill DTC preconditions has reached ECU memory limit


    NEXT
  14. REPLACE AIR FUEL RATIO SENSOR


    1. Replace the air fuel ratio sensor Click here.


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


    1. Connect the intelligent tester to the DLC3.

    2. Turn the power switch on (IG).

    3. Turn the tester on.

    4. Clear the DTCs Click here.

    5. Turn the power switch off and wait for at least 30 seconds.

    6. Drive the vehicle in accordance with the driving pattern described in the Confirmation Driving Pattern.

    7. Enter the following menus: Powertrain / Engine and ECT / Utility / All Readiness.

    8. Input the DTC: P2195 or P2196.

    9. Check the DTC judgment result.

      Result
      Result Proceed to
      NORMAL (DTC is not output) A
      ABNORMAL (DTC P2195 or P2196 is output) B

    B
    A
  16. CHECK FUEL LINE


    1. Check the fuel lines for leaks or blockage.


    NG
    OK