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

DTC    P2A03    A/F Sensor Circuit Slow Response (Bank 2 Sensor 1)

for Preparation Click here


DESCRIPTION

  1. DTC P2A00 indicates malfunctions related to the bank 1 A/F sensor.
  2. DTC P2A03 indicates malfunctions related to the bank 2 A/F sensor.
  3. Bank 1 refers to the bank that includes cylinder No. 1.
  4. Bank 2 refers to the bank that includes cylinder No. 2.
  5. Sensor 1 refers to the sensor mounted in front of the Three-Way Catalytic Converter (TWC) and located near the engine assembly.
Refer to DTC P2195 on page Click here.

DTC No.
DTC Detection Condition
Trouble Area
P2A00
P2A03
Air-Fuel Ratio (A/F) sensor circuit slow response:
Under condition (a), (b) and (c), A/F sensor output voltage changing value below regular changing value in comparison with fuel trim changing value (2 trip detection logic):
(a) Warm engine
(b) Driving at engine speed of between 1,400 rpm and 3,200 rpm
(c) Vehicle speed between 37.5 mph and 75 mph (60 km/h and 120 km/h)
  1. Open or short in A/F sensor (bank 1, 2 sensor 1)
  2. A/F sensor (bank 1, 2 sensor 1)
  3. A/F sensor heater
  4. A/F HTR relay
  5. Open or short in A/F sensor heater and relay circuits
  6. Air induction system
  7. Fuel pressure
  8. Injector
  9. PCV valve and hose
  10. PCV hose connection
  11. ECM

MONITOR DESCRIPTION


A082390E01

The output voltage of the A/F sensor varies in proportion to the air-fuel ratio. Based on these voltage variations, the ECM determines whether the actual air-fuel ratio is rich or lean, and makes adjustments to bring it close to the stoichiometric level. In addition, the ECM checks the fuel injection volume compensation value to determine whether the A/F sensor response time is normal or slow. The ECM calculates the ratio of the variations in both A/F sensor output voltage and the fuel trim value.

WIRING DIAGRAM

Refer to DTC P2195 on page Click here.

INSPECTION PROCEDURE

HINT:
Intelligent tester only:
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 to determine whether the Air-fuel Ratio (A/F) sensor, Heated Oxygen (HO2) 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 and turn the tester ON.
  3. Warm up the engine at an engine speed of 2,500 rpm for approximately 90 seconds.
  4. On the intelligent tester, enter the following menus: Power train / Engine / Active Test / Control the Injection Volume for A/F Sensor.
  5. Perform the Control the Injection Volume for A/F Sensor operation with the engine in an idling condition (press the RIGHT or LEFT button to change the fuel injection volume).
  6. Monitor the output voltages of the A/F and HO2 sensors (AFS B1 S1 and O2S B1 S2 or AFS B2 S1 and O2S B2 S2) displayed on the tester.

HINT:
  1. The Control the Injection Volume for A/F Sensor operation lowers the fuel injection volume by 12.5 % or increases the injection volume by 25 %.
  1. Each sensor reacts in accordance with increases in the fuel injection volume.


Standard: 
Tester Display
(Sensor)
Injection Volume
Status
Voltage
AFS B1 S1 or AFS B2 S1
(A/F)
+25 %
Rich
Less than 3.0
AFS B1 S1 or AFS B2 S1
(A/F)
-12.5 %
Lean
More than 3.35
O2S B1 S2 or O2S B2 S2
(HO2)
+25 %
Rich
 More than 0.55
O2S B1 S2 or O2S B2 S2
(HO2)
-12.5 %
Lean
Less than 0.4

NOTICE:
The Air-Fuel Ratio (A/F) sensor has an output delay of a few seconds and the Heated Oxygen (HO2) sensor has a maximum output delay of approximately 20 seconds.


Case
A/F Sensor (Sensor 1)
Output Voltage
HO2 Sensor (Sensor 2)
Output Voltage
Main Suspected Trouble Area
1
Injection Volume
+25 %
-12.5 %
A103184
Injection Volume
+25 %
-12.5 %
A103184
-
Output Voltage
More than 3.35 V
Less than 3.0 V
A107708
Output Voltage
More than 0.55 V
Less than 0.4 V
A103186
2
Injection Volume
+25 %
-12.5 %
A103184
Injection Volume
+25 %
-12.5 %
A103184
  1. A/F sensor
  2. A/F sensor heater
  3. A/F sensor circuit
Output Voltage
Almost
no reaction
A103185
Output Voltage
More than 0.55 V
Less than 0.4 V
A103186
3
Injection Volume
+25 %
-12.5 %
A103184
Injection Volume
+25 %
-12.5 %
A103184
  1. HO2 sensor
  2. HO2 sensor heater
  3. HO2 sensor circuit
Output Voltage
More than 3.35 V
Less than 3.0 V
A107708
Output Voltage
Almost
no reaction
A103185
4
Injection volume
+25 %
-12.5 %
A103184
Injection Volume
+25 %
-12.5 %
A103184
  1. Injector
  2. Fuel pressure
  3. Gas leakage from exhaust system
    (Air-fuel ratio extremely lean or rich)
Output Voltage
Almost
no reaction
A103185
Output Voltage
Almost
no reaction
A103185
  1. Following the Control the Injection Volume for A/F Sensor procedure enables technicians to check and graph the voltage outputs of both the A/F and HO2 sensors.
  2. To display the graph, enter the following menus: Power train / Engine / Active Test / Control the Injection Volume for A/F Sensor and Data List / AFS B1 S1 and O2S B1 S2 or AFS B2 S1 and O2S B2 S2.

HINT:
  1. DTC P2A00 or P2A03 may be also set, when the air-fuel ratio is stuck rich or lean.
  2. A low A/F 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 A/F 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 intelligent tester. Freeze frame data records the engine conditions when malfunctions are detected. When troubleshooting, freeze frame data can help determine if the vehicle was running or stopped, 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 AND/OR P2A03)

  1. Connect the intelligent tester to the DLC3.

  1. Turn the engine switch on (IG).

  1. Turn the tester ON.

  1. Enter the following menus: Power train / Engine / DTC.

  1. Read DTCs.

    Result: 
    Display (DTC Output)
    		Proceed to
    P2A00 and/or P2A03
    		A
    P2A00 and/or P2A03 and other DTCs
    		B

HINT:
If any DTCs other than P2A00 or P2A03 are output, troubleshoot those DTCs first.



B
GO TO DTC CHART
A


2.READ VALUE USING INTELLIGENT TESTER (OUTPUT VOLTAGE OF A/F SENSOR)

  1. Connect the intelligent tester to the DLC3.

  1. Start the engine.

  1. Turn the tester ON.

  1. Warm up the Air-Fuel Ratio (A/F) sensor at an engine speed of 2,500 rpm for 90 seconds.

  1. On the tester, enter the following menus: Power train / Engine / Data List / AFS B1 S1 or AFS B2 S1 and Engine Speed.



  1. Check the A/F sensor voltage three times, when the engine is in each of the following conditions:

    1. While idling (check for at least 30 seconds)

    2. At an engine speed of approximately 2,500 rpm (without any sudden changes in engine speed)



    3. Raise the engine speed to 4,000 rpm and then quickly release the accelerator pedal so that the throttle valve is fully closed.

      Standard voltage: 
      Condition
      		A/F Sensor Voltage Variation
      		Reference
      (1) and (2)
      		Changes at approximately 3.3 V
      		Between 3.1 V and 3.5 V
      (3)
      		Increases to 3.8 V or more
      		This occurs during engine deceleration
      when fuel-cut performed

      HINT:
      For more information, see the diagrams below.


      A107161E01

      HINT:
      1. If the output voltage of the A/F sensor remains at approximately 3.3 V (see Malfunction Condition diagram) under any conditions, including those above, the A/F sensor may have an open circuit. (this will also happen if the A/F sensor heater has an open circuit.)
      2. If the output voltage of the A/F 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 A/F sensor may have a short circuit.
      3. The ECM stops fuel injection (fuel cut) during engine deceleration. This causes a lean condition and result in a momentary increase in the A/F sensor output voltage.
      4. 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 10 mph (16 km/h) to allow the ECM terminal has been reconnected, the vehicle must be driven over 10 mph (16 km/h) to allow the ECM to learn the closed throttle valve position.
      5. When the vehicle is driven: The output voltage of the A/F 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 A/F sensor is functioning normally.
      6. The A/F 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 A/F sensor or ECM will show a constant voltage result.



NG
Go to step 9
OK


3.PERFORM CONFIRMATION DRIVING PATTERN

NEXT


4.CHECK WHETHER DTC OUTPUT RECURS (DTC P2A00 AND/OR P2A03)

  1. Read DTCs using the intelligent tester.

  1. Enter the following menus: Power train / Engine / DTC.

    Result: 
    Display (DTC Output)
    		Proceed to
    P2A00 and/or P2A03
    		A
    No output
    		B



B
Go to step 8
A


5.REPLACE AIR FUEL RATIO SENSOR

NEXT


6.PERFORM CONFIRMATION DRIVING PATTERN

NEXT


7.CHECK WHETHER DTC OUTPUT RECURS (DTC P2A00 AND/OR P2A03)

  1. Read DTCs using the intelligent tester.

  1. Enter the following menus: Power train / Engine / DTC.

    Result: 
    Display (DTC Output)
    		Proceed to
    No output
    		A
    P2A00 and/or P2A03
    		B



B
REPLACE ECM AND PERFORM CONFIRMATION DRIVING PATTERN
A


8.CONFIRM WHETHER VEHICLE HAS RUN OUT OF FUEL IN PAST


NO
CHECK FOR INTERMITTENT PROBLEMS
YES

DTC CAUSED BY RUNNING OUT OF FUEL 

9.INSPECT AIR FUEL RATIO SENSOR (HEATER RESISTANCE)
A085152E06

  1. Disconnect the E68 or E65 A/F sensor connector.

  1. Measure the resistance of the terminals of the A/F sensor connector.

    Standard resistance (Bank 1 sensor 1):
    Tester Connection
    		Specified Condition
    HA1A (1) - +B (2)
    		1.8 Ω to 3.4 Ω at 20°C (68°F)
    HA1A (1) - A1A- (4)
    		10 kΩ or higher

    Standard resistance (Bank 2 sensor 1):
    Tester Connection
    		Specified Condition
    HA2A (1) - +B (2)
    		1.8 Ω to 3.4 Ω at 20°C (68°F)
    HA2A (1) - A1A- (4)
    		10 kΩ or higher

  1. Reconnect the A/F sensor connector.



NG
REPLACE AIR FUEL RATIO SENSOR
OK


10.INSPECT A/F HTR RELAY
B016200E02

  1. Remove the A/F HTR relay from the engine room No. 2 relay block.

  1. Measure the resistance of the A/F HTR relay.

    Standard resistance:
    Tester Connection
    		Specified Condition
    3 - 5
    		10 kΩ or higher
    3 - 5
    		Below 1 Ω
    (when battery voltage applied to terminals 1 and 2)

  1. Reinstall the A/F HTR relay.



NG
REPLACE A/F HTR RELAY
OK


11.CHECK HARNESS AND CONNECTOR (A/F SENSOR -ECM)
A107711E03

  1. Disconnect the E68 and E65 A/F sensor connector.

  1. Turn the engine switch on (IG).

  1. Measure the voltage between the +B terminal of the A/F sensor connector and body ground.

    Standard voltage:
    Tester Connection
    		Specified Condition
    +B (E68-2) - Body ground
    		9 to 14 V
    +B (E65-2) - Body ground
    		9 to 14 V

  1. Turn the engine switch off.

  1. Disconnect the E45 ECM connector.

  1. Measure the resistance.

    Standard resistance (Check for open):
    Tester Connection
    		Specified Condition
    HA1A( E68-1) - HA1A (E45-6)
    		Below 1 Ω
    A1A+ (E68-3) - A1A+ (E45-18)
    		Below 1 Ω
    A1A- (E68-4) - A1A- (E45-17)
    		Below 1 Ω
    HA2A (E65-1) - HA2A (E45-4)
    		Below 1 Ω
    A2A+ (E65-3) - A2A+ (E45-28)
    		Below 1 Ω
    A2A- (E65-4) - A2A- (E45-27)
    		Below 1 Ω

    Standard resistance (Check for short):
    Tester Connection
    		Specified Condition
    HA1A( E68-1) or HA1A (E45-6) - Body ground
    		10 kΩ or higher
    A1A+ (E68-3) or A1A+ (E45-18) - Body ground
    		10 kΩ or higher
    A1A- (E68-4) or A1A- (E45-17) - Body ground
    		10 kΩ or higher
    HA2A (E65-1) or HA2A (E45-4) - Body ground
    		10 kΩ or higher
    A2A+ (E65-3) or A2A+ (E45-28) - Body ground
    		10 kΩ or higher
    A2A- (E65-4) or A2A- (E45-27) - Body ground
    		10 kΩ or higher

  1. Reconnect the ECM connector.

  1. Reconnect the A/F sensor connector.



NG
REPAIR OR REPLACE HARNESS OR CONNECTOR
OK


12.CHECK AIR INDUCTION SYSTEM

  1. Check the air induction system for vacuum leakage.

OK:
No leakage from air induction system.



NG
REPAIR OR REPLACE AIR INDUCTION SYSTEM
OK


13.CHECK PCV HOSE

OK:
PCV hose is connected correctly and is not damaged.



NG
REPAIR OR REPLACE PCV HOSE
OK


14.CHECK FUEL PRESSURE (HIGH PRESSURE SIDE)

  1. Check the fuel pressure.



NG
REPAIR OR REPLACE FUEL SYSTEM
OK


15.INSPECT FUEL INJECTOR

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



NG
REPLACE FUEL INJECTOR
OK


16.REPLACE AIR FUEL RATIO SENSOR

NEXT


17.PERFORM CONFIRMATION DRIVING PATTERN

NEXT


18.CHECK WHETHER DTC OUTPUT RECURS (DTC P2A00 AND/OR P2A03)

  1. Read DTCs using the intelligent tester.

  1. Enter the following menus: Power train / Engine / DTC.

    Result: 
    Display (DTC Output)
    		Proceed to
    No output
    		A
    P2A00 and/or P2A03
    		B



B
REPLACE ECM
A


19.CONFIRM WHETHER VEHICLE HAS RUN OUT OF FUEL IN PAST


NO
CHECK FOR INTERMITTENT PROBLEMS
YES

DTC CAUSED BY RUNNING OUT OF FUEL