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

for Preparation Click here


DESCRIPTION

HINT:
Refer to DTC P2195 (Click here).

DTC No.
DTC Detection Condition
Trouble Area
P2A00
Calculated value for air fuel ratio sensor response rate deterioration level is less than threshold (2 trip detection logic)
  1. Air fuel ratio sensor (sensor 1)
  2. Intake system
  3. Fuel injection
  4. Fuel pump
  5. Fuel line
  6. ECM

MONITOR DESCRIPTION

After 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 A/F control is performed for approximately 15 to 20 seconds after preconditions are met in order to measure the air fuel ratio sensor response rate. During active A/F control, the ECM forcibly increases and decreases the injection volume 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 A/F control and uses it to calculate the air fuel ratio sensor response rate deterioration level.
If the value for air fuel ratio sensor response rate deterioration level is beyond the threshold, the ECM interprets this as a malfunction and sets the DTC.

A115363E21


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 following DTCs not present
P0016 (VVT System - Misalignment)
P0017 (Exhaust VVT System - Misalignment)
P0031, P0032 (Air Fuel Ratio Sensor Heater - Sensor 1)
P0102, P0103 (Mass Air Flow Meter)
P0112, P0113 (Intake Air Temperature Sensor)
P0115, P0117, P0118 (Engine Coolant Temperature Sensor)
P0125 (Insufficient Engine Coolant Temperature for Closed Loop Fuel Control)
P0120, P0121 P0122, P0123, P0220, P0222, P0223, P2135 (Throttle Position Sensor)
P0128 (Thermostat)
P0171, P0172 (Fuel System)
P0301, P0302, P0303, P0304 (Misfire)
P0335 (Crankshaft Position Sensor)
P0340, P0342, P0343 (Camshaft Position Sensor)
P0451, P0452, P0453 (EVAP System)
P0500 (Vehicle Speed Sensor)
P0505 (Vehicle Speed Sensor IAC Valve)
P219A (Air Fuel Ratio Imbalance)
Active air fuel ratio control
Performing
Active air fuel ratio control performed when following conditions met
-
Battery voltage
11 V or more
Engine coolant temperature
75°C (167°F) or more
Idling
Off
Engine speed
1000 rpm or more, and less than 4000 rpm
Air fuel ratio sensor status
Activated
Fuel-cut
Off
Engine load
10% or more, and less than 80%
Shift position
2nd or more
Catalyst monitor
Not yet
Intake air amount
3.2 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 Checking Monitor Status (Click here).

CONFIRMATION DRIVING PATTERN


A231470E74

  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.

    HINT:
    1. If a pending DTC is output, the system is malfunctioning.
    2. 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
    1. DTC judgment completed
    2. System normal
    ABNORMAL
    1. DTC judgment completed
    2. System abnormal
    INCOMPLETE
    1. DTC judgment not completed
    2. Perform driving pattern after confirming DTC enabling conditions
    N/A
    1. Unable to perform DTC judgment
    2. Number of DTCs which do not fulfill DTC preconditions has reached ECU memory limit

    HINT:
    1. If the judgment result shows NORMAL, the system is normal.
    2. If the judgment result shows ABNORMAL, the system has a malfunction.
    3. 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.

    HINT:
    1. If a pending DTC is output, the system is malfunctioning.
    2. 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
    1. DTC judgment completed
    2. System normal
    ABNORMAL
    1. DTC judgment completed
    2. System abnormal
    INCOMPLETE
    1. DTC judgment not completed
    2. Perform driving pattern after confirming DTC enabling conditions
    N/A
    1. Unable to perform DTC judgment
    2. Number of DTCs which do not fulfill DTC preconditions has reached ECU memory limit

    HINT:
    1. If the judgment result shows NORMAL, the system is normal.
    2. If the judgment result shows ABNORMAL, the system has a malfunction.
    3. 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).

    HINT:
    1. If a permanent DTC is output, the system is malfunctioning.
    2. If no permanent DTC is output, the system is normal.

WIRING DIAGRAM

Refer to DTC P2195 (Click here).

INSPECTION PROCEDURE

HINT:
  1. DTC P2A00 may be also set, when the air fuel ratio is stuck rich or lean.
  2. 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.
  3. 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.
  4. 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 be helpful in determining whether the vehicle was running or stopped, whether the engine was warmed up or not, whether the air fuel ratio was lean or rich, as well as other data recorded at the time of a malfunction.
  5. Sensor 1 refers to the sensor closest to the engine assembly.
  6. Sensor 2 refers to the sensor farthest away from the engine assembly.
1.CHECK ANY OTHER DTCS OUTPUT (IN ADDITION TO DTC P2A00)

  1. Connect the Techstream to the DLC3.

  1. Turn the ignition switch to ON.

  1. Turn the Techstream on.

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

  1. Read the DTCs.

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

    HINT:
    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.

  1. Start the engine.

  1. Turn the Techstream on.

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

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

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

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

    HINT:
    1. Change the fuel injection volume within the range of -12% to +12%. The injection volume can be changed in fine gradations.
    2. 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.
    3. 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
    1. 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.
    2. 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.
    3. Lean/Rich: During the Control the Injection Volume Active Test, the output voltage of the heated oxygen sensor alternates correctly.

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


B
Go to step 4

C
Go to step 8
A


3.CHECK WHETHER DTC OUTPUT RECURS (DTC P2A00)

  1. Connect the Techstream to the DLC3.

  1. Turn the ignition switch to ON.

  1. Turn the Techstream on.

  1. Clear the DTCs (Click here).

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

  1. Turn the ignition switch to ON.

  1. Turn the Techstream on.

  1. Start the engine and warm it up.

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

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

  1. Input the DTC: P2A00.

  1. Check the DTC judgment result.

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


B
Go to step 8
A

CHECK FOR INTERMITTENT PROBLEMS (Click here)  

4.INSPECT AIR FUEL RATIO SENSOR (HEATER RESISTANCE)

  1. Inspect 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).



NG
REPAIR OR REPLACE INTAKE SYSTEM
OK


6.CHECK FUEL PRESSURE

  1. Check the fuel pressure (Click here).



NG
Go to step 12
OK


7.INSPECT FUEL INJECTOR ASSEMBLY

  1. Inspect 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).


NEXT


9.CHECK WHETHER DTC OUTPUT RECURS (DTC P2A00)

  1. Connect the Techstream to the DLC3.

  1. Turn the ignition switch to ON.

  1. Turn the Techstream on.

  1. Clear the DTCs (Click here).

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

  1. Turn the ignition switch to ON.

  1. Turn the Techstream on.

  1. Start the engine and warm it up.

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

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

  1. Input the DTC: P2A00.

  1. 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.

  1. Turn the ignition switch to ON.

  1. Turn the Techstream on.

  1. Clear the DTCs (Click here).

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

  1. Turn the ignition switch to ON.

  1. Turn the Techstream on.

  1. Start the engine and warm it up.

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

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

  1. Input the DTC: P2A00.

  1. Check that the DTC judgment result is NORMAL.


NEXT

END 

12.CHECK FUEL LINE

  1. Check the fuel lines for leaks or blockage.



NG
REPAIR OR REPLACE FUEL LINE
OK

REPLACE FUEL PUMP (Click here)