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

for Preparation Click here

DESCRIPTION

HINT:

Sensor 1 refers to the sensor mounted in front of the Three-Way Catalytic Converter (TWC) and located near the engine assembly.

CONFIRMATION DRIVING PATTERN

HINT:

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

1. Connect an intelligent tester to the DLC3.
   
2. Turn the ignition switch to ON.
   
3. Turn the tester on.
   
4. Enter the following menus: Powertrain / Engine and ECT / DTC / Clear.
   
5. Clear DTCs.
   
6. Start the engine and warm it up (Proceed to "A").
   
7. Drive the vehicle at a constant speed between 64 km/h and 120 km/h (40 mph and 75 mph) for 3 minutes or more (Proceed to "B").
   
8. Turn the ignition switch off.
   
9. Repeat steps Procedure "A" and "B" above again.
   
10. Enter the following menus: Powertrain / Engine and ECT / DTC.
    
11. Check if any DTCs (any pending DTCs) are set.
    

WIRING DIAGRAM

INSPECTION PROCEDURE

NOTICE:

Inspect the fuses for circuits related to this system before performing the following 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 2500 rpm for approximately 90 seconds.
   
4. Enter the following menus: Powertrain / Engine and ECT / Active Test / Control the Injection Volume for A/F Sensor.
   
5. Perform the Active Test 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 (AF Voltage B1S1 and O2S B1S2) 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%.
   
2. Each sensor reacts in accordance with increases and decreases in the fuel injection volume.
   

NOTICE:

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.

Case	A/F Sensor (Sensor 1) Output Voltage	HO2 Sensor (Sensor 2) Output Voltage	Main Suspected Trouble Area
1			-
2			A/F sensor A/F sensor heater A/F sensor circuit
3			HO2 sensor HO2 sensor heater HO2 sensor circuit
4			Injector Fuel pressure Gas leak from exhaust system (Air-fuel ratio extremely rich or lean)

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: Powertrain / Engine and ECT / Active Test / Control the Injection Volume for A/F Sensor / A/F Control System / AF Voltage B1S1 and O2S B1S2.
   

HINT:

1. DTC P2A00 may be 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 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. Connect an intelligent tester to the DLC3.
   

2. Turn the ignition switch to ON.
   

3. Turn the tester on.
   

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

5. Read DTCs.
   

   Result 

   Result	Proceed to
   P2A00	A
   P2A00 and other DTCs	B

   HINT:

   If any DTCs relating to the A/F sensor (DTCs for the A/F sensor heater or A/F sensor admittance) are output, troubleshoot those DTCs first.

B	GO TO DTC CHART (Click here)

A

1. Connect the intelligent tester to the DLC3.
   

2. 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.

3. Turn the tester on.
   

4. Enter the following menus: Powertrain / Engine and ECT / Active Test / Control the EGR Step Position.
   

5. Check the MAP in Data List and the idling condition while performing Active Test.
   

   OK:

   MAP and idling condition change in response to EGR step position.
   

Standard:

-	EGR Step Position (Active Test)
	0 Steps	0 to 30 Steps	30 to 40 Steps or Higher
Idling condition	Steady idling	Engine changes from steady to rough idling	Engine changes from rough idling to engine stall
MAP value (Data List)	28 to 48 kPa (EGR valve is fully closed)	MAP value is at least +10 to 15 kPa higher than when EGR valve is fully closed	80 to 110 kPa (After engine stall)

HINT:

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

B	Go to step 4

A

1. Connect the intelligent tester to the DLC3.
   

2. Turn the ignition switch to ON.
   

3. Turn the tester on.
   

4. Clear the DTC.
   

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

6. 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.

7. Switch the ECM from normal mode to check mode.
   

8. Drive the vehicle at 60 km/h (37 mph) with the shift lever in B.
   

   CAUTION:

   1. Strictly observe speed limits and traffic laws when performing the confirmation drive pattern.
      

9. Perform fuel-cut operation for 5 seconds or more, with the accelerator pedal fully released.
   

   HINT:

   1. If the deceleration was not completed, perform the confirmation driving pattern again.
      

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

11. Input the DTCs to be confirmed.
    

12. Check the DTC judgment result.
    

HINT:

1. If the DTC judgment result is INCOMPLETE or UNKNOWN, drive the vehicle again at 60 km/h (37 mph) with the shift lever in B, perform fuel-cut operation for 5 seconds or more with the accelerator pedal fully released, and check the DTC judgment result.
   

B	GO TO DTC CHART (Click here)

A

1. Disconnect the air fuel ratio sensor connector.
   

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

   Standard Resistance:

   Tester Connection	Condition	Specified Condition
   1 (HA1A) - 2 (+B)	20°C (68°F)	1.8 to 3.4 Ω
   1 (HA1A) - 4 (A1A-)	Always	10 kΩ or higher

   Text in Illustration 

   *1	Component without harness connected: (Air Fuel Ratio Sensor)

3. Reconnect the air fuel ratio sensor.
   

NG	REPLACE AIR FUEL RATIO SENSOR (Click here)

OK

1. Disconnect the air fuel ratio sensor connector.
   

2. Turn the ignition switch to ON.
   

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

   Standard Voltage:

   Tester Connection	Switch Condition	Specified Condition
   B34-2 (+B) - Body ground	Ignition switch ON	11 to 14 V

   Text in Illustration 

   *1	Front view of wire harness connector: (to Air Fuel Ratio Sensor)
   *2	Front view of wire harness connector: (to ECM)

4. Turn the ignition switch off.
   

5. Disconnect the ECM connector.
   

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

   Standard Resistance (Check for Open):

   Tester Connection	Condition	Specified Condition
   B34-3 (A1A+) - B8-103 (A1A+)	Always	Below 1 Ω
   B34-4 (A1A-) - B8-126 (A1A-)	Always	Below 1 Ω
   B34-1 (HA1A) - B8-104 (HA1A)	Always	Below 1 Ω

   Standard Resistance (Check for Short):

   Tester Connection	Condition	Specified Condition
   B34-3 (A1A+) or B8-103 (A1A+) - Body ground	Always	10 kΩ or higher
   B34-4 (A1A-) or B8-126 (A1A-) - Body ground	Always	10 kΩ or higher
   B34-1 (HA1A) or B8-104 (HA1A) - Body ground	Always	10 kΩ or higher

7. Reconnect the ECM connector.
   

8. Reconnect the air fuel ratio sensor connector.
   

NG	REPAIR OR REPLACE HARNESS OR CONNECTOR

OK

NEXT

1. Connect an intelligent tester to the DLC3.
   

2. Turn the ignition switch to ON.
   

3. Turn the tester on.
   

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

5. Read DTCs.
   

   Result 

   Result	Proceed to
   P2A00	A
   No output	B

B	CHECK FOR INTERMITTENT PROBLEMS (Click here)

A

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

NEXT

NEXT

1. Connect an intelligent tester to the DLC3.
   

2. Turn the ignition switch to ON.
   

3. Turn the tester on.
   

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

5. Read DTCs.
   

   Result 

   Result	Proceed to
   No output	A
   P2A00	B

B	REPAIR OR REPLACE CAUSE OF EXTREMELY RICH OR LEAN ACTUAL AIR FUEL RATIO (Click here)

A
END