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

HINT:
  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.
  6. Although the DTC titles say oxygen sensor, these DTCs relate to the Air-Fuel Ratio (A/F) sensor.
  7. Sensor 1 refers to the sensor mounted in front of the Three-Way Catalytic Converter (TWC) and located near the engine assembly.
The A/F 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 time. If the A/F sensor malfunctions, the ECM is unable to control the air-fuel ratio accurately.
The A/F sensor is the planar type and is integrated with the 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), a current flows into 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 (TWC) is used in order to convert the carbon monoxide (CO), hydrocarbon (HC), and nitrogen oxide (NOx) into less harmful substances. To allow the TWC 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 A/F sensor is the current output element, a current is converted to a voltage inside the ECM. Any measurements taken at the A/F sensor or ECM connectors will show a constant voltage.

A107164E17


DTC No.
DTC Detection Conditions
Trouble Area
P2A00
P2A03
Calculated value for air-fuel ratio (A/F) sensor response rate deterioration level is less than threshold
  1. Open or short in A/F sensor circuit
  2. A/F sensor
  3. ECM

CONFIRMATION DRIVING PATTERN

HINT:
Performing this confirmation pattern will activate the A/F sensor response monitor.

A079199E96

  1. Connect an intelligent tester to the DLC3.
  2. Turn the ignition switch to the ON position.
  3. Turn the tester on.
  4. Clear the DTCs (where set).
  5. Start the engine and warm it up (Procedure "A").
  6. Drive the vehicle at between 40 km/h and 120 km/h (25 mph and 75 mph) for 3 minutes. However, the vehicle should be driven at a constant speed (Procedure "B").
  7. Select the following menu items: Powertrain / Engine / DTC.
  8. Check if any DTCs (any pending DTCs) are set.

WIRING DIAGRAM

Refer to DTC P2195 (Click here).

INSPECTION PROCEDURE

HINT:
Intelligent tester only:
Malfunctioning areas can be identified by performing "Control the Injection Volume for A/F Sensor" provided in the Active Test . "Control the Injection Volume for A/F Sensor" 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 "Control the Injection Volume for A/F Sensor" 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: Powertrain / Engine / Active Test / Control the Injection Volume for A/F Sensor.
  5. Perform "Control the Injection Volume for A/F Sensor" 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. "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.

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

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. Fuel pressure
  2. 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. Performing "Control the Injection Volume for A/F Sensor" enables technicians to check and graph the voltage outputs of both the A/F and HO2 sensors.
  2. The following A/F Control procedure enables the technician to check and graph the voltage output of both the heated oxygen sensors. To display the graph, select the following menu items on the tester: View / Line Graph.

HINT:
  1. DTC P2A00 or P2A03 may also be set when the air-fuel ratio remains 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. 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 (Click here).
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 ignition switch to the ON position.

  1. Turn the tester on.

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

  1. Read the 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 (Click here)
A


2.INSPECT AIR FUEL RATIO SENSOR (HEATER RESISTANCE)
A126269E12

  1. Disconnect the C15 or C35 A/F sensor connector.

  1. Measure the resistance according to the value(s) in the table below.

    Standard resistance:
    Bank 1 sensor 1:
    Tester Connection
    		Condition
    		Specified Condition
    HA1A (1) - +B (2)
    		20°C (68°F)
    		1.8 to 3.4 Ω
    HA1A (1) - A1A- (4)
    		-
    		10 kΩ or higher
    Bank 2 sensor 1:
    Tester Connection
    		Condition
    		Specified Condition
    HA2A (1) - +B (2)
    		20°C (68°F)
    		1.8 to 3.4 Ω
    HA2A (1) - A2A- (4)
    		-
    		10 kΩ or higher

  1. Reconnect the A/F sensor connector.



NG
REPLACE AIR FUEL RATIO SENSOR (Click here)
OK


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


    A127715E17

  1. Disconnect the C15 and C35 A/F sensor connectors.

  1. Turn the ignition switch to the ON position.

  1. Measure the voltage according to the value(s) in the table below.

    Standard voltage:
    Tester Connection
    		Specified Condition
    +B (C15-2) - Body ground
    		9 to 14 V
    +B (C35-2) - Body ground
    		9 to 14 V

  1. Turn the ignition switch off.

  1. Disconnect the C58 (RHD) or C55 (LHD) ECM connector.

  1. Measure the resistance according to the value(s) in the table below.

    Standard resistance (Check for open):
    RHD:
    Tester Connection
    		Specified Condition
    HA1A (C15-1) - HA1A (C58-86)
    		Below 1 Ω
    A1A+ (C15-3) - A1A+ (C58-93)
    		Below 1 Ω
    A1A- (C15-4) - A1A- (C58-116)
    		Below 1 Ω
    HA2A (C35-1) - HA2A (C58-109)
    		Below 1 Ω
    A2A+ (C35-3) - A2A+ (C58-120)
    		Below 1 Ω
    A2A- (C35-4) - A2A- (C58-119)
    		Below 1 Ω
    LHD:
    Tester Connections
    		Specified Condition
    HA1A (C15-1) - HA1A (C55-86)
    		Below 1 Ω
    A1A+ (C15-3) - A1A+ (C55-93)
    		Below 1 Ω
    A1A- (C15-4) - A1A- (C55-116)
    		Below 1 Ω
    HA2A (C35-1) - HA2A (C55-109)
    		Below 1 Ω
    A2A+ (C35-3) - A2A+ (C55-120)
    		Below 1 Ω
    A2A- (C35-4) - A2A- (C55-119)
    		Below 1 Ω

    Standard resistance (Check for open):
    RHD:
    Tester Connection
    		Specified Condition
    HA1A (C15-1) or HA1A (C58-86) - Body ground
    		10 kΩ or higher
    A1A+ (C15-3) or A1A+ (C58-93) - Body ground
    		10 kΩ or higher
    A1A- (C15-4) or A1A- (C58-116) - Body ground
    		10 kΩ or higher
    HA2A (C35-1) or HA2A (C58-109) - Body ground
    		10 kΩ or higher
    A2A+ (C35-3) or A2A+ (C58-120) - Body ground
    		10 kΩ or higher
    A2A- (C35-4) or A2A- (C58-119)- Body ground
    		10 kΩ or higher
    LHD:
    Tester Connection
    		Specified Condition
    HA1A (C15-1) or HA1A (C55-86) - Body ground
    		10 kΩ or higher
    A1A+ (C15-3) or A1A+ (C55-93) - Body ground
    		10 kΩ or higher
    A1A- (C15-4) or A1A- (C55-116) - Body ground
    		10 kΩ or higher
    HA2A (C35-1) or HA2A (C55-109) - Body ground
    		10 kΩ or higher
    A2A+ (C35-3) or A2A+ (C55-120) - Body ground
    		10 kΩ or higher
    A2A- (C35-4) or A2A- (C55-119) - 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


4.PERFORM CONFIRMATION DRIVING PATTERN

NEXT


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

  1. Read the DTCs using the intelligent tester.

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

    Result:

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


B
REPLACE ECM (Click here)
A


6.REPLACE AIR FUEL RATIO SENSOR

  1. Replace the air fuel ratio sensor (Click here).


NEXT


7.PERFORM CONFIRMATION DRIVING PATTERN

NEXT


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

  1. Read the DTCs using the intelligent tester.

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

    Result:

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


B
REPLACE ECM (Click here)
A

END