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

for Preparation Click here


DESCRIPTION

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
  2. Intake system
  3. Fuel injector assembly
  4. Fuel system
  5. EGR valve assembly
  6. 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 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 air fuel 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 air fuel 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.

A115363E43


MONITOR STRATEGY


Required Sensors/Components (Main)
Air fuel ratio sensor
Frequency of Operation
Once per driving cycle

TYPICAL ENABLING CONDITIONS


Active air fuel ratio control
Performing
Active air fuel ratio control performed when following conditions met
-
Auxiliary battery voltage
11 V or higher
Engine coolant temperature
75°C (167°F) or higher
Idling
OFF
Engine speed
Less than 4000 rpm
Air fuel ratio sensor status
Activated
Fuel-cut
OFF
Engine load
10 to 70%
Catalyst monitor
Not yet
Mass air flow
6.0 to 12 gm/sec

CONFIRMATION DRIVING PATTERN

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


A231470E60

  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 is 75°C (167°F) or higher [A].
  9. Drive the vehicle at approximately 60 to 100 km/h (37 to 62 mph) for 10 minutes or more [B].

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

  10. Enter the following menus: Powertrain / Engine and ECT / DTC [C].
  11. 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.

  12. Enter the following menus: Powertrain / Engine and ECT / Utility / All Readiness.
  13. Input the DTC: P2A00.
  14. Check the DTC judgment result.

    Tester 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
    UNKNOWN
    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 UNKNOWN, perform the following procedure.

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

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

  16. Check the DTC judgment result [E].

WIRING DIAGRAM

Refer to DTC P2195 (Click here).

INSPECTION PROCEDURE

HINT:
  1. DTC P2A00 may also be set when the air fuel ratio remains 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. Sensor 1 refers to the sensor closet to the engine assembly.
  5. Sensor 2 refers to the sensor farthest away from the engine assembly.
  6. 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.

1.CHECK ANY OTHER DTCS OUTPUT (IN ADDITION TO DTC P2A00)

  1. Connect the intelligent tester to the DLC3.

  1. Turn the power switch on (IG).

  1. Turn the tester on.

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

  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 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
GO TO DTC CHART (Click here)
A


2.PERFORM ACTIVE TEST USING INTELLIGENT TESTER (INJECTION VOLUME)

  1. Connect the intelligent tester to the DLC3.

  1. Turn the power switch on (IG).

  1. Turn the tester on.

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

  1. Start the engine.

  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 / All Data / 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 tester.

    HINT:
    1. Change the fuel injection volume within the range of - 12.0% to +12.0%. 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.


    Standard 
    Tester Display (Sensor)
    		Injection Volume
    		Status
    		Voltage
    AFS Voltage B1S1
    (Air fuel ratio)
    		+12%
    		Rich
    		Below 3.1 V
    -12%
    		Lean
    		Higher than 3.4 V
    O2S B1S2
    (Heated oxygen)
    		+12%
    		Rich
    		Higher than 0.55 V
    -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) is consistently higher than 3.4 V, and the heated oxygen sensor output voltage (O2S) is consistently below 0.4 V.
    Rich: During the Control the Injection Volume Active Test, the AFS Voltage is consistently below 3.1 V, and the O2S 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.

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.PERFORM CONFIRMATION DRIVING PATTERN

  1. Connect the intelligent tester to the DLC3.

  1. Turn the power switch on (IG).

  1. Turn the tester on.

  1. Clear the DTCs (Click here).

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

  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 for vacuum leaks (Click here).

    OK:
    No leaks in intake system.



NG
REPAIR OR REPLACE INTAKE SYSTEM
OK


6.CHECK FUEL PRESSURE

  1. Check fuel pressure (Click here).



NG
Go to step 14
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 intelligent tester to the DLC3.

  1. Turn the power switch on (IG).

  1. Turn the tester on.

  1. Clear the DTCs (Click here).

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

  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.PERFORM ACTIVE TEST USING INTELLIGENT TESTER (CONTROL THE EGR STEP POSITION)

  1. Connect the intelligent tester to the DLC3.

  1. Turn the power switch on (IG).

  1. Turn the tester on.

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

  1. Start the engine and warm it up until the engine coolant temperature reaches 75°C (167°F) or higher.

    HINT:
    The A/C switch and all accessory switches should be off.

  1. Enter the following menus: Powertrain / Engine and ECT / Active Test / Control the EGR Step Position / Data List / All Data / Throttle Idle Position and MAP.

  1. Confirm that the Throttle Idle Position is ON and check the engine idling condition and MAP values in the Data List while performing the Active Test.

    HINT:
    1. Do not leave the EGR valve open for 10 seconds or more during the Active Test.
    2. Be sure to return the EGR valve to step 0 when the Active Test is completed.
    3. Do not open the EGR valve 30 steps or more during the Active Test.

    OK:
    MAP and idling condition change in response to EGR step position when Throttle Idle Position is ON in Data List.


    Standard:

    -
    		EGR Step Position (Active Test)
    0 Steps
    		0 to 30 Steps
    Idling condition
    		Steady idling
    		Idling changes from steady to rough idling or stalls
    MAP
    (Data List)
    		MAP value is 20 to 40 kPa (150 to 300 mmHg)
    (EGR valve is fully closed)
    		MAP value is at least +10 kPa (75 mmHg) higher than when EGR valve is fully closed

    HINT:
    During Active Test, if the idling condition does not change in response to EGR step position, then there is probably a malfunction in the EGR valve.

    Result 
    Result
    		Proceed to
    Outside of standard range
    		A
    Within standard range
    		B



B
Go to step 12
A


11.INSPECT EGR VALVE ASSEMBLY

  1. Remove the EGR valve assembly (Click here).

  1. Check if the EGR valve is stuck open.

    OK:
    EGR valve is tightly closed.



NG
REPLACE EGR VALVE ASSEMBLY (Click here)
OK


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.

  1. Turn the power switch on (IG).

  1. Turn the tester on.

  1. Clear the DTCs (Click here).

  1. Turn the power switch off and wait for 30 seconds.

  1. Drive the vehicle in accordance with the driving pattern described in the 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 is NORMAL.


NEXT

END 

14.INSPECT FUEL PUMP

  1. Inspect the fuel pump (Click here).



NG
REPLACE FUEL PUMP (Click here)
OK

REPAIR OR REPLACE FUEL LINE