SFI SYSTEM, Diagnostic DTC:P2A00

DTC Code DTC Name
P2A00 A/F Sensor Circuit Slow Response (Bank 1 Sensor 1)

DESCRIPTION

Tech Tips


  • Refer to DTC P2195 Click here.

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

DTC No. DTC Detection Condition Trouble Area
P2A00 The calculated value for the air fuel ratio sensor response rate deterioration level is less than the threshold (2 trip detection logic).

  • Air fuel ratio sensor (sensor 1)

  • Intake system

  • Fuel injector assembly

  • Fuel pump

  • Fuel line

  • ECM

MONITOR DESCRIPTION

After the engine is warmed up, the ECM performs air fuel ratio feedback control to maintain the air fuel ratio at the stoichiometric level. In addition, active air fuel ratio control is performed for approximately 10 seconds after preconditions are met in order to measure the air fuel ratio sensor response rate. During active air fuel ratio control, the ECM forcibly increases and decreases the injection volume by a certain amount, based on the stoichiometric air fuel ratio learned during normal air fuel ratio control, and measures the air fuel ratio sensor response rate. The ECM receives a signal from the air fuel ratio sensor while performing active air fuel ratio control and uses it to calculate the air fuel ratio sensor response rate deterioration level.

If the value for the air fuel ratio sensor response rate deterioration level is less than the threshold, the ECM interprets this as a malfunction and stores the DTC.

A01HQ9KE32

MONITOR STRATEGY

Related DTCs P2A00: Air fuel ratio sensor (sensor 1) slow response
Required Sensors/Components (Main) Air fuel ratio sensor
Required Sensors/Components (Related)

Vehicle speed sensor

Crankshaft position sensor
Frequency of Operation Once per driving cycle
Duration 10 to 15 seconds
MIL Operation 2 driving cycles
Sequence of Operation None

TYPICAL ENABLING CONDITIONS

Monitor runs whenever the following DTCs are not stored

P0016 (VVT system - misalignment)

P0017 (Exhaust VVT system - misalignment)

P0031, P0032, P101D (Air fuel ratio sensor heater)

P0102, P0103 (Mass air flow meter)

P0112, P0113 (Intake air temperature sensor)

P0115, P0117, P0118 (Engine coolant temperature sensor)

P0120, P0121, P0122, P0123, P0220, P0222, P0223, P2135 (Throttle position sensor)

P0125 (Insufficient coolant temperature for closed loop fuel control)

P0128 (Thermostat)

P0171, P0172 (Fuel system)

P0301 - P0304 (Misfire)

P0335 (Crankshaft position sensor)

P0451, P0452, P0453 (EVAP system)

P0500 (Vehicle speed sensor)

P0505 (IAC valve)

P219A (Air fuel ratio imbalance)
Active air fuel ratio control Performing
Active air fuel ratio control is performed when the following conditions met -
Battery voltage 11 V or higher
Engine coolant temperature 75°C (167°F) or higher
Idling Off
Engine speed 1200 rpm or higher, and less than 4000 rpm
Air fuel ratio sensor status Activated
Fuel-cut Off
Engine load 10% or higher, and less than 70%
Shift position 2nd or more
Catalyst monitor Not yet
Mass air flow 4 gm/sec or more, and less than 16 gm/sec

TYPICAL MALFUNCTION THRESHOLDS

Response rate deterioration level Less than 0.12 V

MONITOR RESULT

Refer to detailed information in Checking Monitor Status Click here.

P2A00: O2 Sensor / RES RATE B1S1
Monitor ID Test ID Scaling Unit Description
$01 $8E Multiply by 0.001 V A/F sensor deterioration level

CONFIRMATION DRIVING PATTERN

Tech Tips

Performing this confirmation pattern will activate the air fuel ratio sensor response monitor.

A01HN1WE74

  1. Connect the Techstream to the DLC3.

  2. Turn the ignition switch to ON.

  3. Turn the Techstream on.

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

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

  6. Turn the ignition switch to ON and turn the Techstream on.

  7. Enter the following menus: Powertrain / Engine and ECT / Monitor / Current Monitor.

  8. Check that O2 Sensor / Current is Incomplete.

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

  10. Drive the vehicle at approximately 60 km/h (37 mph) for 10 minutes or more in a city area [B].

    CAUTION:

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

  11. Check the monitor result values on the Techstream by entering the following menus: Powertrain / Engine and ECT / Monitor / Current Monitor / O2 Sensor / Details / RES RATE B1S1.

  12. If the values indicated on the Techstream do not change, perform Readiness Monitor Drive Pattern for the air fuel ratio sensor and heated oxygen sensor Click here.

  13. Note the value of Test Results.

  14. Enter the following menus: Powertrain / Engine and ECT / Trouble Codes [C].

  15. 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.

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

  17. Input the DTC: P2A00.

  18. Check the DTC judgment result.

    Techstream 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 the following procedure.

  19. Drive the vehicle at a speed between 75 and 100 km/h (47 and 62 mph) for 10 minutes [D].

    CAUTION:

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

  20. Enter the following menus: Powertrain / Engine and ECT / Trouble Codes [C].

  21. 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.

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

  23. Input the DTC: P2A00.

  24. Check the DTC judgment result.

    Techstream 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 is INCOMPLETE or N/A, drive the vehicle again under an increased load and then recheck the judgment result.

  25. If no pending DTC is output, perform a universal trip and check for permanent DTCs Click here.

    Tech Tips


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

    • If no permanent DTC is output, the system is normal.

WIRING DIAGRAM

Refer to DTC P0031 Click here.

INSPECTION PROCEDURE

Note

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

Tech Tips


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

  • 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.

  • Read freeze frame data using the Techstream. 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.

  • 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 P2A00)


    1. Connect the Techstream to the DLC3.

    2. Turn the ignition switch to ON.

    3. Turn the Techstream on.

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

    5. Read the DTCs.

      Result
      Result Proceed to
      DTC P2A00 is output A
      DTC P2A00 and other DTCs are output B

      Tech Tips

      If any DTCs other than P2A00 are output, troubleshoot those DTCs first.


    B

    GO TO DTC CHART Click here

    A

  2. PERFORM ACTIVE TEST USING TECHSTREAM (CONTROL THE INJECTION VOLUME)


    1. Connect the Techstream to the DLC3.

    2. Start the engine.

    3. Turn the Techstream on.

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

    5. Enter the following menus: Powertrain / Engine and ECT / Active Test / Control the Injection Volume / Gas AF Control / AFS Voltage B1S1 and O2S B1S2.

    6. Perform the Control the Injection Volume operation with the engine idling.

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

      Tech Tips


      • Change the fuel injection volume within the range of -12% to +12%. The injection volume can be changed in fine gradations.

      • 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.

      Techstream Display (Sensor) Injection Volume Status Voltage

      AFS Voltage B1S1

      (Air fuel ratio)

      		 +12% Rich Below 3.1 V

      AFS Voltage B1S1

      (Air fuel ratio)

      		 -12% Lean Higher than 3.4 V

      O2S B1S2

      (Heated oxygen)

      		 +12% Rich Higher than 0.55 V

      O2S B1S2

      (Heated oxygen)

      		 -12% 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/Rich Lean/Rich Normal A
      Lean Lean Actual air fuel ratio lean B
      Rich Rich Actual air fuel ratio rich B
      Lean Lean/Rich Air fuel ratio sensor malfunction C
      Rich Lean/Rich Air fuel ratio sensor malfunction C

      • Lean: During the Control the Injection Volume 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 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 Active Test, the output voltage of the heated oxygen sensor alternates correctly.

      Tech Tips

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


    B

    Click here

    C

    REPLACE AIR FUEL RATIO SENSOR Click here

    A

  3. CHECK WHETHER DTC OUTPUT RECURS (DTC P2A00)


    1. Connect the Techstream to the DLC3.

    2. Turn the ignition switch to ON.

    3. Turn the Techstream on.

    4. Clear the DTCs Click here.

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

    6. Turn the ignition switch to ON.

    7. Turn the Techstream on.

    8. Start the engine and warm it up.

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

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

    11. Input the DTC: P2A00.

    12. Check the DTC judgment result.

      Result
      Result Proceed to
      NORMAL (DTC is not output) A
      ABNORMAL (DTC P2A00 is output) B

    B

    REPLACE AIR FUEL RATIO SENSOR Click here

    A

    CHECK FOR INTERMITTENT PROBLEMS Click here

  4. INSPECT AIR FUEL RATIO SENSOR (HEATER RESISTANCE)


    1. Inspect the air fuel ratio sensor Click here.

      Tech Tips

      Perform "Inspection After Repair" after replacing the air fuel ratio sensor Click here.


    NG

    REPLACE AIR FUEL RATIO SENSOR Click here

    OK

  5. CHECK INTAKE SYSTEM


    1. Check the intake system Click here.

      Tech Tips

      Perform "Inspection After Repair" after repairing or replacing the intake system Click here.


    NG

    REPAIR OR REPLACE INTAKE SYSTEM

    OK

  6. CHECK FUEL PRESSURE


    1. Check the fuel pressure Click here.


    NG

    CHECK FUEL LINE Click here

    OK

  7. INSPECT FUEL INJECTOR ASSEMBLY


    1. Inspect the fuel injector assembly Click here.

      Tech Tips

      Perform "Inspection After Repair" after replacing the fuel injector assembly Click here.


    NG

    REPLACE FUEL INJECTOR ASSEMBLY Click here

    OK

  8. REPLACE AIR FUEL RATIO SENSOR


    1. Replace the air fuel ratio sensor Click here.

      Tech Tips

      Perform "Inspection After Repair" after replacing the air fuel ratio sensor Click here.


    NEXT

  9. CHECK WHETHER DTC OUTPUT RECURS (DTC P2A00)


    1. Connect the Techstream to the DLC3.

    2. Turn the ignition switch to ON.

    3. Turn the Techstream on.

    4. Clear the DTCs Click here.

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

    6. Turn the ignition switch to ON.

    7. Turn the Techstream on.

    8. Start the engine and warm it up.

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

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

    11. Input the DTC: P2A00.

    12. Check the DTC judgment result.

      Result
      Result Proceed to
      ABNORMAL (DTC P2A00 is output) A
      NORMAL (DTC is not output) B

    B

    END

    A

  10. REPLACE ECM


    1. Replace the ECM Click here.


    NEXT

  11. CHECK WHETHER DTC OUTPUT RECURS (DTC P2A00)


    1. Connect the Techstream to the DLC3.

    2. Turn the ignition switch to ON.

    3. Turn the Techstream on.

    4. Clear the DTCs Click here.

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

    6. Turn the ignition switch to ON.

    7. Turn the Techstream on.

    8. Start the engine and warm it up.

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

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

    11. Input the DTC: P2A00.

    12. Check that the DTC judgment result is NORMAL.


    NEXT

    END

  12. CHECK FUEL LINE


    1. Check the fuel lines for leaks or blockage.

      Tech Tips

      Perform "Inspection After Repair" after replacing the fuel pump Click here.


    NG

    REPAIR OR REPLACE FUEL LINE

    OK

    REPLACE FUEL PUMP Click here