Toyota Corolla Cross: O2 Sensor Circuit Range/Performance Bank 1 Sensor 1 Signal Rate of Change Below Threshold (P2A0026)

DESCRIPTION

Refer to DTC P003012.

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HINT:

Although the DTC titles say oxygen sensor, this DTC relate to the air fuel ratio sensor (sensor 1).

DTC No.	Detection Item	DTC Detection Condition	Trouble Area	MIL	Note
P2A0026	O2 Sensor Circuit Range/Performance Bank 1 Sensor 1 Signal Rate of Change Below Threshold	The calculated value for the air fuel ratio sensor (sensor 1) response rate deterioration level is less than the threshold (2 trip detection logic).	Air fuel ratio sensor (sensor 1) Intake system Port fuel injector assembly Direct fuel injector assembly Fuel pressure (for low pressure) Fuel pressure (for high pressure) Fuel system EGR valve assembly ECM	Comes on / Does not come on	SAE Code: P2A00 DTC for Mexico Models : Appies

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 ratio control is performed for approximately 30 seconds after preconditions are met in order to measure the air fuel ratio sensor (sensor 1) response rate. During active air fuel ratio control, the ECM forcibly increases and decreases the injection volume by a certain amount, based on the stoichiometric air fuel ratio learned during normal air fuel ratio control, and measures the air fuel ratio sensor (sensor 1) response rate. The ECM receives a signal from the air fuel ratio sensor (sensor 1) while performing active air fuel ratio control and uses it to calculate the air fuel ratio sensor (sensor 1) response rate deterioration level.

If the value for the air fuel ratio sensor (sensor 1) response rate deterioration level is less than the threshold, the ECM interprets this as a malfunction and stores the DTC.

MONITOR STRATEGY

Required Sensors/Components	Air fuel ratio sensor (sensor 1)
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	-
Engine coolant temperature	75°C (167°F) or higher
Idling	Off
Engine speed	1000 rpm or higher, and less than 3000 rpm
Air fuel ratio sensor status	Activated
Engine load	10% or higher, and less than 100%
Catalyst monitor	Not yet
Mass air flow	4 gm/sec or more, and less than 16 gm/sec

CONFIRMATION DRIVING PATTERN

HINT:

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

1. Connect the GTS to the DLC3.
2. Turn the ignition switch to ON.
3. Turn the GTS 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.
7. Turn the GTS on.
8. Start the engine and warm it up until the engine coolant temperature is 75°C (167°F) or higher [A].
9. With the engine running, drive the vehicle at approximately 60 to 100 km/h (37 to 62 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.

10. Enter the following menus: Powertrain / Engine / Trouble Codes [C].
11. Read the pending DTCs.

    HINT:

    • If a pending DTC is output, the system is malfunctioning.
    • If a pending DTC is not output, perform the following procedure.
12. Enter the following menus: Powertrain / Engine / Utility / All Readiness.
13. Input the DTC: P2A0026.
14. Check the DTC judgment result.

    GTS Display	Description
    NORMAL	DTC judgment completed System normal
    ABNORMAL	DTC judgment completed System abnormal
    INCOMPLETE	DTC judgment not completed Perform driving pattern after confirming DTC enabling conditions

    HINT:

    • If the judgment result shows NORMAL, the system is normal.
    • If the judgment result shows ABNORMAL, the system has a malfunction.
    • If the judgment result shows INCOMPLETE and no pending DTC is output, perform the following procedure.
15. With the engine running, 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.

16. Enter the following menus: Powertrain / Engine / Trouble Codes [E].
17. Read the pending DTCs.

    HINT:

    • If a pending DTC is output, the system is malfunctioning.
    • If a pending DTC is not output, perform the following procedure.
18. Enter the following menus: Powertrain / Engine / Utility / All Readiness.
19. Input the DTC: P2A0026.
20. Check the DTC judgment result.

    GTS Display	Description
    NORMAL	DTC judgment completed System normal
    ABNORMAL	DTC judgment completed System abnormal
    INCOMPLETE	DTC judgment not completed Perform driving pattern after confirming DTC enabling conditions

    HINT:

    • If the judgment result shows NORMAL, the system is normal.
    • If the judgment result shows ABNORMAL, the system has a malfunction.
    • If the judgment result shows INCOMPLETE, drive the vehicle again under an increased load and then recheck the judgment result.

WIRING DIAGRAM

Refer to DTC P003012.

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CAUTION / NOTICE / HINT

NOTICE:

Inspect the fuses for circuits related to this system before performing the following procedure.

HINT:

• DTC P2A0026 may be also stored when the air fuel ratio is stuck at rich or lean.
• A low air fuel ratio sensor (sensor 1) voltage could be caused by a rich air fuel mixture. Check for conditions that would cause the engine to run rich.
• A high air fuel ratio sensor (sensor 1) voltage could be caused by a lean air fuel mixture. Check for conditions that would cause the engine to run lean.
• Sensor 1 refers to the sensor closest to the engine assembly.
• Sensor 2 refers to the sensor farthest away from the engine assembly.
• Read freeze frame data using the GTS. 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.

PROCEDURE

1.	CHECK ANY OTHER DTCS OUTPUT (IN ADDITION TO DTC P2A0026)

(a) Read the DTCs.

Powertrain > Engine > Trouble Codes

Result	Proceed to
DTC P2A0026 is output	A
DTC P2A0026 and other DTCs are output	B

HINT:

If any DTCs other than P2A0026 are output, troubleshoot those DTCs first.

B

GO TO DTC CHART

A

2.	PERFORM ACTIVE TEST USING GTS (CONTROL THE INJECTION VOLUME FOR A/F SENSOR)

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

(b) Warm up the air fuel ratio sensors at an engine speed of 2500 rpm for 90 seconds.

(c) Enter the following menus.

Powertrain > Engine > Active Test

Active Test Display
Control the Injection Volume for A/F Sensor

Data List Display
Coolant Temperature
A/F (O2) Sensor Current B1S1
A/F (O2) Sensor Current B1S2

(d) Perform the Control the Injection Volume for A/F Sensor operation with the engine idling.

(e) Monitor the output values of the air fuel ratio sensor (sensor 1) and air fuel ratio sensor (sensor 2) (A/F (O2) Sensor Current B1S1 and A/F (O2) Sensor Current B1S2) displayed on the GTS.

HINT:

• The Control the Injection Volume for A/F Sensor operation lowers the fuel injection volume by 12.5% or increases the injection volume by 12.5%.
• The air fuel ratio sensor (sensor 1) has an output delay of a few seconds and the air fuel ratio sensor (sensor 2) has a maximum output delay of approximately 20 seconds.
• If the sensor output value does not change (almost no reaction) while performing the Active Test, the sensor may be malfunctioning.

Standard

GTS Display (Sensor)	Injection Volume	Status	Value
A/F (O2) Sensor Current B1S1 (Air fuel ratio (sensor 1))	12.5%	Rich	Below -0.075 mA
	-12.5%	Lean	More than 0.037 mA
A/F (O2) Sensor Current B1S2 (Air fuel ratio (sensor 2))	12.5%	Rich	Below -0.86 mA
	-12.5%	Lean	More than 0.33 mA

Status of A/F (O2) Sensor Current B1S1	Status of A/F (O2) Sensor Current B1S2	Air Fuel Ratio Condition and Air Fuel Ratio Sensor (Sensor 1) Condition	Proceed to
Lean/Rich	Lean/Rich	Normal	A
Lean	Lean	Actual air fuel ratio lean	B
Rich	Rich	Actual air fuel ratio rich
Lean	Lean/Rich	Air fuel ratio sensor (sensor 1) malfunction	C
Rich	Lean/Rich	Air fuel ratio sensor (sensor 1) malfunction

• Lean: During the Control the Injection Volume for A/F Sensor Active Test, the air fuel ratio sensor (sensor 1) output current (A/F (O2) Sensor Current B1S1) is consistently more than 0.037 mA, and the air fuel ratio sensor (sensor 2) output current (A/F (O2) Sensor Current B1S2) is consistently more than 0.33 mA.
• Rich: During the Control the Injection Volume for A/F Sensor Active Test, the air fuel ratio sensor (sensor 1) output current (A/F (O2) Sensor Current B1S1) is consistently below -0.075 mA, and the air fuel ratio sensor (sensor 2) output current (A/F (O2) Sensor Current B1S2) is consistently below -0.86 mA.
• Lean/Rich: During the Control the Injection Volume for A/F Sensor Active Test, the output current of the air fuel ratio sensor (sensor 1) or air fuel ratio sensor (sensor 2) alternate correctly.

HINT:

Refer to "Data List / Active Test" [A/F (O2) Sensor Voltage B1S1, A/F (O2) Sensor Voltage B2S1, A/F (O2) Sensor Current B1S2 and A/F (O2) Sensor Current B2S2].

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B

GO TO STEP 7

C

GO TO STEP 16

A

3.

CLEAR DTC

(a) Clear the DTCs.

Powertrain > Engine > Clear DTCs

(b) Turn the ignition switch off and wait for at least 30 seconds.

NEXT

4.	CHECK WHETHER DTC OUTPUT RECURS (DTC P2A0026)

(a) Drive the vehicle in accordance with the driving pattern described in the Confirmation Driving Pattern.

(b) Enter the following menus.

Powertrain > Engine > Utility

Tester Display
All Readiness

(c) Input the DTC: P2A0026.

(d) Check the DTC judgment result.

Result	Proceed to
NORMAL (DTCs are not output)	A
ABNORMAL (DTC P2A0026 is output)	B

A

END

B

5.	PERFORM ACTIVE TEST USING GTS (CONTROL THE EGR STEP POSITION)

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

HINT:

The A/C switch and all accessories should be off.

(b) Enter the following menus.

Powertrain > Engine > Active Test

Active Test Display
Control the EGR Step Position

Data List Display
Engine Speed
Intake Manifold Absolute Pressure
Coolant Temperature

(c) Check the engine idling condition and Intake Manifold Absolute Pressure values in the Data List while performing the Active Test.

NOTICE:

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

OK:

The value of Intake Manifold Absolute Pressure and Engine Speed change in response to EGR step position.

Standard:

-	Control the EGR Step Position (Active Test)
	0 Steps	0 to 30 Steps
Idling condition	Steady idling	Idling changes from steady to rough idling or engine stalls
Intake Manifold Absolute Pressure (Data List)	Intake Manifold Absolute Pressure value is 18 to 38 kPa(abs) (2.6 to 5.5 psi(abs)) (EGR valve is fully closed)	Intake Manifold Absolute Pressure value is at least +10 kPa (1.45 psi) 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.

OK

GO TO STEP 16

NG

6.	INSPECT EGR VALVE ASSEMBLY

(a) Remove the EGR valve assembly.

Click here

(b) Check if the EGR valve is stuck open.

OK:

EGR valve is tightly closed.

HINT:

Perform "Inspection After Repair" after replacing the EGR valve assembly.

Click here

OK

GO TO STEP 16

NG

REPLACE EGR VALVE ASSEMBLY

7.	INSPECT AIR FUEL RATIO SENSOR (SENSOR 1) (HEATER RESISTANCE)

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HINT:

Perform "Inspection After Repair" after replacing the air fuel ratio sensor (sensor 1).

Click here

NG

REPLACE AIR FUEL RATIO SENSOR (SENSOR 1)

OK

8.	CHECK INTAKE SYSTEM

(a) Check the intake system for vacuum leaks.

Click here

OK:

No leaks in the intake system.

HINT:

Perform "Inspection After Repair" after repairing or replacing the intake system.

Click here

NG

REPAIR OR REPLACE INTAKE SYSTEM

OK

9.	CHECK FOR EXHAUST GAS LEAK

(a) Check for exhaust gas leaks.

OK:

No gas leaks.

HINT:

Perform "Inspection After Repair" after repairing or replacing the exhaust system.

Click here

NG

REPAIR OR REPLACE EXHAUST SYSTEM

OK

10.	PERFORM ACTIVE TEST USING GTS (CONTROL THE EGR STEP POSITION)

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

HINT:

The A/C switch and all accessories should be off.

(b) Enter the following menus.

Powertrain > Engine > Active Test

Active Test Display
Control the EGR Step Position

Data List Display
Engine Speed
Intake Manifold Absolute Pressure
Coolant Temperature

(c) Check the engine idling condition and Intake Manifold Absolute Pressure values in the Data List while performing the Active Test.

NOTICE:

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

OK:

The value of Intake Manifold Absolute Pressure and Engine Speed change in response to EGR step position.

Standard:

-	Control the EGR Step Position (Active Test)
	0 Steps	0 to 30 Steps
Idling condition	Steady idling	Idling changes from steady to rough idling or engine stalls
Intake Manifold Absolute Pressure (Data List)	Intake Manifold Absolute Pressure value is 18 to 38 kPa(abs) (2.6 to 5.5 psi(abs)) (EGR valve is fully closed)	Intake Manifold Absolute Pressure value is at least +10 kPa (1.45 psi) 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.

OK

GO TO STEP 12

NG

11.	INSPECT EGR VALVE ASSEMBLY

(a) Remove the EGR valve assembly.

Click here

(b) Check if the EGR valve is stuck open.

OK:

EGR valve is tightly closed.

HINT:

Perform "Inspection After Repair" after replacing the EGR valve assembly.

Click here

NG

REPLACE EGR VALVE ASSEMBLY

OK

12.	CHECK FUEL PRESSURE (LOW PRESSURE SIDE)

Click here

NG

GO TO STEP 19

OK

13.	INSPECT PORT FUEL INJECTOR ASSEMBLY

(a) Inspect the port fuel injector assembly (whether fuel volume is high or low, and whether injection pattern is poor).

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HINT:

Perform "Inspection After Repair" after replacing the port fuel injector assembly.

Click here

NG

REPLACE PORT FUEL INJECTOR ASSEMBLY

OK

14.	READ VALUE USING GTS (FUEL PRESSURE (HIGH))

(a) Enter the following menus.

Powertrain > Engine > Data List

Tester Display
Engine Speed
Coolant Temperature
Fuel Pressure (High)
Injection Mode

(b) Start the engine and warm it up until the engine coolant temperature is 75°C (167°F) or higher with all the accessories switched off.

(c) According to the display on the GTS, read the Data List.

Standard:

GTS Display	Condition	Specified Condition
Fuel Pressure (High)	Shift position: P A/C: Off Engine warmed up Engine Speed: 3000 rpm Injection Mode: Direct	2400 to 20000 kPag

NG

REPAIR OR REPLACE FUEL SYSTEM (FOR HIGH PRESSURE)

OK

15.	INSPECT DIRECT FUEL INJECTOR ASSEMBLY

Click here

HINT:

Perform "Inspection After Repair" after replacing the direct fuel injector assembly.

Click here

NG

REPLACE DIRECT FUEL INJECTOR ASSEMBLY

OK

16.	REPLACE AIR FUEL RATIO SENSOR (SENSOR 1)

Click here

HINT:

Perform "Inspection After Repair" after replacing the air fuel ratio sensor (sensor 1).

Click here

NEXT

17.

CLEAR DTC

(a) Clear the DTCs.

Powertrain > Engine > Clear DTCs

(b) Turn the ignition switch off and wait for at least 30 seconds.

NEXT

18.	CHECK WHETHER DTC OUTPUT RECURS (DTC P2A0026)

(a) Drive the vehicle in accordance with the driving pattern described in the Confirmation Driving Pattern.

(b) Enter the following menus.

Powertrain > Engine > Utility

Tester Display
All Readiness

(c) Input the DTC: P2A0026.

(d) Check the DTC judgment result.

Result	Proceed to
NORMAL (DTCs are not output)	A
ABNORMAL (DTC P2A0026 is output)	B

A

END

B

REPLACE ECM

19.	CHECK FUEL LINE (FOR LOW PRESSURE SIDE)

(a) Check the fuel lines (for low pressure side) for leaks or blockage.

HINT:

Perform "Inspection After Repair" after replacing the fuel pump (for low pressure side).

Click here

OK

REPLACE FUEL PUMP (FOR LOW PRESSURE SIDE) for 2WD: Click here for AWD: Click here

NG

REPAIR OR REPLACE FUEL LINE (FOR LOW PRESSURE SIDE)

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