Toyota Avalon (XX50) 2019-2022 Service & Repair Manual: Catalyst System Efficiency Below Threshold Bank 1 (P042000)

MONITOR DESCRIPTION

The ECM uses air fuel ratio sensors mounted in front of and behind the Three-Way Catalytic Converter (TWC) to monitor its efficiency.

The first sensor, the air fuel ratio sensor (sensor 1), sends pre-catalyst information to the ECM. The second sensor, the air fuel ratio sensor (sensor 2), sends post-catalyst information to the ECM.

In order to detect any deterioration in the three-way catalytic converter, the ECM calculates the oxygen storage capacity of the three-way catalytic converter. This calculation is based on the output current of the air fuel ratio sensor (sensor 2) while performing active air fuel ratio control.

The oxygen storage capacity value is an indication of the oxygen storage capacity of the three-way catalytic converter. When the vehicle is being driven with a warm engine, active air fuel ratio control is performed for approximately 30 seconds. When it is performed, the ECM deliberately sets the air fuel ratio to lean or rich levels. If the cycle of the waveform for the air fuel ratio sensor (sensor 2) is long, the oxygen storage capacity is great. There is a direct correlation between the air fuel ratio sensor (sensor 2) and the oxygen storage capacity of the three-way catalytic converter.

The ECM uses the oxygen storage capacity value to determine the state of the three-way catalytic converter. If any deterioration has occurred, the ECM will illuminate the MIL and store a DTC.

This system determines the deterioration of the entire catalyst system (including the front and rear catalysts), by using the oxygen storage capacity value of the front catalyst, that is more sensitive than the rear catalyst, as the representative value. Therefore, be sure to replace the front and rear catalysts together when catalyst replacement is necessary.

CATALYST LOCATION

NOTICE:

When replacing the exhaust manifold (*3) and the front exhaust pipe assembly (*4) in order to replace the three-way catalytic converter, it is not necessary to replace the air fuel ratio sensor (sensor 1) (*1) and the air fuel ratio sensor (sensor 2) (*2).

MONITOR STRATEGY

TYPICAL ENABLING CONDITIONS

TYPICAL MALFUNCTION THRESHOLDS

MONITOR RESULT

Refer to detailed information in Checking Monitor Status.

Click here

CONFIRMATION DRIVING PATTERN

HINT:

• It is necessary for the response of the air fuel ratio sensor (sensor 2) to be normal in order to confirm DTC P042000. Therefore, perform the confirmation driving pattern for the air fuel ratio sensor (sensor 2) monitor before performing the confirmation driving pattern for the catalyst efficiency monitor.
• Performing this confirmation driving pattern will activate the catalyst efficiency monitor. This is very useful for verifying the completion of a repair.
• After repair has been completed, clear the DTC and then check that the vehicle has returned to normal by performing the following All Readiness check procedure.

  Click here

• When clearing the permanent DTCs, refer to the "CLEAR PERMANENT DTC" procedure.

  Click here

1. Connect the Techstream to the DLC3.
2. Turn the power switch on (IG).
3. Turn the Techstream on.
4. Clear the DTCs (even if no DTCs are stored, perform the clear DTC procedure).
5. Turn the power switch off and wait for at least 30 seconds.
6. Turn the power switch on (IG).
7. Turn the Techstream on.
8. Enter the following menus: Powertrain / Engine / Monitor / Current Monitor.
9. Check that Catalyst Efficiency / Current is Incomplete.
10. Put the engine in Inspection Mode (Maintenance Mode).

    Click here

11. Start the engine and warm it up until the engine coolant temperature is 75°C (167°F) or higher with the shift lever in P [A].

    HINT:

    In order to keep the idle stable, turn the A/C and all other electric loads off and do not perform any shift operations.

12. With the engine running, drive the vehicle at approximately 75 km/h (47 mph) for 10 minutes or more [B].

    CAUTION:

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

    HINT:

    • Drive the vehicle while keeping the engine load as constant as possible.
    • If the engine stops, further depress the accelerator pedal to restart the engine.
13. With the shift lever in S and the engine running, drive the vehicle at 75 km/h (47 mph), and then decelerate the vehicle by releasing the accelerator pedal for 5 seconds or more to perform the fuel-cut [C].

    CAUTION:

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

    HINT:

    If the engine stops, further depress the accelerator pedal to restart the engine.

14. Enter the following menus: Powertrain / Engine / Monitor / Current Monitor / O2 Sensor / Details / SLOW RESPONSE B1S2 [D].
15. Check the Test Value for SLOW RESPONSE B1S2.

    HINT:

    • If Test Value displays a value larger than 0, perform the following procedure, as the O2 Sensor monitor is finished.
    • If Test Value displays 0, perform step [C] until it displays a value larger than 0, as the O2 Sensor monitor is not finished.
16. Turn the power switch off and wait for at least 30 seconds [F].
17. Turn the power switch on (IG).
18. Turn the Techstream on.
19. Put the engine in Inspection Mode (Maintenance Mode).

    Click here

20. Start the engine and warm it up until the engine coolant temperature is 75°C (167°F) or higher [G].
21. With the engine running, drive the vehicle at approximately 75 km/h (47 mph) for 10 minutes or more [H].

    CAUTION:

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

    HINT:

    • Drive the vehicle while keeping the engine load as constant as possible.
    • The monitor item will change to Complete as the Catalyst Efficiency monitor operates.
    • If the engine stops, further depress the accelerator pedal to restart the engine.
22. Enter the following menus: Powertrain / Engine / Trouble Codes [I].
23. Check if any DTCs are stored.

    HINT:

    • If the monitor item does not change to Complete, and no DTCs are stored, perform the following procedure.
    • [A] to [I]: Normal judgment procedure.

      The normal judgment procedure is used to complete DTC judgment and also used when clearing permanent DTCs.

    • When clearing the permanent DTCs, do not disconnect the cable from the auxiliary battery terminal or attempt to clear the DTCs during this procedure, as doing so will clear the universal trip and normal judgment histories.
24. With the engine running, drive the vehicle at approximately 100 km/h (62 mph) for 10 minutes or more [J].

    CAUTION:

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

    HINT:

    • Drive the vehicle while keeping the engine load as constant as possible.
    • The monitor item will change to Complete as the Catalyst Efficiency monitor operates.
    • If the engine stops, further depress the accelerator pedal to restart the engine.
25. Enter the following menus: Powertrain / Engine / Trouble Codes [K].
26. Check if any DTCs are stored.

    HINT:

    If the monitor item does not change to Complete, and no DTCs are stored, extend the driving time.

27. Enter the following menus: Powertrain / Engine / Utility / All Readiness.
28. Input the DTC: P042000.
29. Check the DTC judgment result.

    Techstream 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 is NORMAL, the system is normal.
    • If the judgment result is ABNORMAL, the system has a malfunction.
    • [A] to [K]: Normal judgment procedure.

      The normal judgment procedure is used to complete DTC judgment and also used when clearing permanent DTCs.

    • When clearing the permanent DTCs, do not disconnect the cable from the auxiliary battery terminal or attempt to clear the DTCs during this procedure, as doing so will clear the universal trip and normal judgment histories.

CAUTION / NOTICE / HINT

NOTICE:

• Vehicle Control History may be stored in the hybrid vehicle control ECU assembly if the engine is malfunctioning. Certain vehicle condition information is recorded when Vehicle Control History is stored. Reading the vehicle conditions recorded in both the Freeze Frame Data and Vehicle Control History can be useful for troubleshooting.

  Click here

  (Select Powertrain in Health Check and then check the time stamp data.)

  Click here

• If any "Engine Malfunction" Vehicle Control History item has been stored in the hybrid vehicle control ECU assembly, make sure to clear it. However, as all Vehicle Control History items are cleared simultaneously, if any Vehicle Control History items other than "Engine Malfunction" are stored, make sure to perform any troubleshooting for them before clearing Vehicle Control History.

  Click here

HINT:

• If a malfunction cannot be found when troubleshooting DTC P042000, a lean or rich abnormality may be the cause. Perform troubleshooting by following the inspection procedure for P017100 (System Too Lean) and P017200 (System Too Rich).
• 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 Techstream. 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

(a) Connect the Techstream to the DLC3.

(b) Turn the power switch on (IG).

(c) Turn the Techstream on.

(d) Enter the following menus: Powertrain / Engine / Trouble Codes.

(e) Read the DTCs.

HINT:

If any DTCs other than P042000 are output, troubleshoot those DTCs first.

B

GO TO DTC CHART

A

(a) Connect the Techstream to the DLC3.

(b) Turn the power switch on (IG).

(c) Turn the Techstream on.

(d) Put the engine in Inspection Mode (Maintenance Mode).

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

(f) Idle the engine for 5 minutes or more with the shift lever in P.

(g) Enter the following menus: Powertrain / Engine / Active Test / Control the Injection Volume for A/F Sensor / Data List / Coolant Temperature, A/F (O2) Sensor Current B1S1 and A/F (O2) Sensor Current B1S2.

(h) Change the fuel injection volume using the Techstream, and monitor the output current of the air fuel ratio sensor (sensor 1) (A/F (O2) Sensor Current B1S1) and air fuel ratio sensor (sensor 2) (A/F (O2) Sensor Current B1S2) displayed on the Techstream.

HINT:

• The Active Test "Control the Injection Volume for A/F Sensor" can be used to lower the fuel injection volume by 12.5% or increase the injection volume by 12.5%.
• The air fuel ratio sensor (sensor 1) is displayed as A/F (O2) Sensor Current B1S1, and the air fuel ratio sensor (sensor 2) is displayed as A/F (O2) Sensor Current B1S2 on the Techstream.
• 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 current does not change (almost no reaction) while performing the Active Test, the sensor may be malfunctioning.

Standard:

• 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 Current B1S1, A/F (O2) Sensor Current B1S2].

Click here

B

GO TO STEP 6

C

GO TO STEP 7

D

GO TO STEP 9

A

(a) Check for exhaust gas leaks.

OK:

No gas leaks in exhaust system.

NG

GO TO STEP 13

OK

(a) Connect the Techstream to the DLC3.

(b) Turn the power switch on (IG).

(c) Turn the Techstream on.

(d) Put the engine in Inspection Mode (Maintenance Mode).

(e) 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.

(f) Enter the following menus: Powertrain / Engine / Active Test / Control the EGR Step Position / Data List / Intake Manifold Absolute Pressure, Coolant Temperature and Engine Independent.

(g) Confirm that the value of Data List item Engine Independent is "Operate" then check the value of Intake Manifold Absolute Pressure while performing the Active Test.

NOTICE:

• Make sure that the value of Data List item Engine Independent is "Operate" while performing the Active Test.
• 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 changes in response to the EGR step position when the value of Engine Independent is "Operate".

Standard:

HINT:

• If the value of Data List item Engine Independent is "Not Opr" when the engine is idling, charge control is being performed. Perform the Active Test after charge control is complete ("Operate" is displayed).
• While performing the Active Test, if the increase in the value of Intake Manifold Absolute Pressure is small, the EGR valve assembly may be malfunctioning.
• Even if the EGR valve assembly is malfunctioning, rough idling or an increase in the value of Intake Manifold Absolute Pressure may occur while performing the Active Test. However, the amount that the value of Intake Manifold Absolute Pressure increases will be smaller than normal.

OK

GO TO STEP 16

NG

(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

(a) Replace the 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

GO TO STEP 14

(a) Check for exhaust gas leaks.

OK:

No gas leaks in exhaust system.

NG

GO TO STEP 13

OK

(a) Replace the air fuel ratio sensor (sensor 2).

Click here

HINT:

Perform "Inspection After Repair" after replacing the air fuel ratio sensor (sensor 2).

Click here

NEXT

GO TO STEP 14

(a) Check for exhaust gas leaks.

OK:

No gas leaks in exhaust system.

NG

GO TO STEP 13

OK

(a) Connect the Techstream to the DLC3.

(b) Turn the power switch on (IG).

(c) Turn the Techstream on.

(d) Put the engine in Inspection Mode (Maintenance Mode).

(e) 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.

(f) Enter the following menus: Powertrain / Engine / Active Test / Control the EGR Step Position / Data List / Intake Manifold Absolute Pressure, Coolant Temperature and Engine Independent.

(g) Confirm that the value of Data List item Engine Independent is "Operate" then check the value of Intake Manifold Absolute Pressure while performing the Active Test.

NOTICE:

• Make sure that the value of Data List item Engine Independent is "Operate" while performing the Active Test.
• 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 changes in response to the EGR step position when the value of Engine Independent is "Operate".

Standard:

HINT:

• If the value of Data List item Engine Independent is "Not Opr" when the engine is idling, charge control is being performed. Perform the Active Test after charge control is complete ("Operate" is displayed).
• While performing the Active Test, if the increase in the value of Intake Manifold Absolute Pressure is small, the EGR valve assembly may be malfunctioning.
• Even if the EGR valve assembly is malfunctioning, rough idling or an increase in the value of Intake Manifold Absolute Pressure may occur while performing the Active Test. However, the amount that the value of Intake Manifold Absolute Pressure increases will be smaller than normal.

OK

GO TO STEP 12

NG

(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

(a) Check the cause of extremely rich or lean actual air fuel ratio, referring to the DTC P017100 and P017200 Inspection Procedure.

Click here

NEXT

GO TO STEP 14

(a) Repair or replace exhaust system.

HINT:

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

Click here

NEXT

(a) Connect the Techstream to the DLC3.

(b) Turn the power switch on (IG).

(c) Turn the Techstream on.

(d) Clear the DTCs.

(e) Turn the power switch off and wait for at least 30 seconds.

NEXT

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

(b) Enter the following menus: Powertrain / Engine / Trouble Codes.

(c) Read the DTCs.

A

END

B

NOTICE:

When replacing the exhaust manifold and the front exhaust pipe assembly in order to replace the three-way catalytic converter, it is not necessary to replace the air fuel ratio sensor (sensor 1) and the air fuel ratio sensor (sensor 2).

HINT:

Confirm the replacement parts, referring to the illustration in the Catalyst Location.

(a) Replace the exhaust manifold (TWC: Front catalyst).

Click here

(b) Replace the front exhaust pipe assembly (TWC: Rear catalyst).

Click here

NEXT

END