DTC P0420-00: Catalyst System Efficiency Below Threshold Bank 1; DTC P0430-00: Catalyst System Efficiency Below Threshold Bank 2 [01/2017 - 04/2020]: Procedure

CHECK ANY OTHER DTCS OUTPUT (IN ADDITION TO DTC P0420-00 AND/OR P0430-00)

Connect the Techstream to the DLC3.
Turn the power switch on (IG).
Turn the Techstream on.
Enter the following menus: Powertrain / Engine / Trouble Codes.

Read the DTCs.

Powertrain > Engine > Trouble Codes

Result

Result	Proceed to
DTC P0420-00 and/or P0430-00 is output	A
DTC P0420-00 and/or P0430-00 and other DTCs are output	B

HINT:

If any DTCs other than P0420-00 and/or P0430-00 are output, troubleshoot those DTCs first.

Result:

GO TO DTC CHART. Refer to DIAGNOSTIC TROUBLE CODE CHART [01/2017 - 09/2018] , or refer to DIAGNOSTIC TROUBLE CODE CHART [09/2018 - 04/2020]

Result:

See step 2

CHECK PCV HOSE CONNECTIONS

Check the PCV hose connections.

PCV valve and hose are connected correctly and are not damaged.

Result

Proceed to
OK
NG

Result:

See step 4

Result:

See step 3

REPAIR OR REPLACE PCV HOSE

Repair or replace the PCV hose.

Result

Proceed to
NEXT

Result:

See step 4

PERFORM ACTIVE TEST USING TECHSTREAM (CONTROL THE INJECTION VOLUME FOR A/F SENSOR)

Connect the Techstream to the DLC3.
Turn the power switch on (IG).
Turn the Techstream on.

Put the engine in Inspection Mode (2WD for measuring Exhaust Gas).

Powertrain > Hybrid Control > Utility

Tester Display
Inspection Mode

Start the engine and warm it up until the engine coolant temperature is 75°C (167°F) or higher.
Idle the engine for 5 minutes or more with park (P) selected.

Enter the following menus: Powertrain / Engine / Active Test / Control the Injection Volume for A/F Sensor / Data List / A/F (O2) Sensor Voltage B1S1 and A/F (O2) Sensor Current B1S2 or A/F (O2) Sensor Voltage B2S1 and A/F (O2) Sensor Current B2S2.

Powertrain > Engine > Active Test

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

Data List Display
A/F (O2) Sensor Voltage B1S1
A/F (O2) Sensor Voltage B2S1
A/F (O2) Sensor Current B1S2
A/F (O2) Sensor Current B2S2

Change the fuel injection volume using the Techstream, and monitor the output voltage of the air fuel ratio sensor (sensor 1) [A/F (O2) Sensor Voltage B1S1 or A/F (O2) Sensor Voltage B2S1] and air fuel ratio sensor (sensor 2) [A/F (O2) Sensor Current B1S2 or A/F (O2) Sensor Current B2S2] 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) 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

Techstream Display (Sensor)	Injection Volume	Status	Value
A/F (O2) Sensor Voltage B1S1 A/F (O2) Sensor Voltage B2S1 (Air fuel ratio (sensor 1))	12.5%	Rich	Below 3.1 V
	-12.5%	Lean	Higher than 3.4 V
A/F (O2) Sensor Current B1S2 A/F (O2) Sensor Current B2S2 (Air fuel ratio (sensor 2))	12.5%	Rich	Below -0.86 mA
	-12.5%	Lean	Higher than 0.33 mA

Result

Status of A/F (O2) Sensor Voltage B1S1 or A/F (O2) Sensor Voltage B2S1	Status of A/F (O2) Sensor Current B1S2 or A/F (O2) Sensor Current B2S2	Actual air fuel ratio, air fuel ratio sensor (sensor 1) and air fuel ratio sensor (sensor 2) condition	Main Suspected Trouble Area	Proceed to
Lean/Rich	Lean/Rich	Normal	Three-way catalytic converter Gas leak from exhaust system EGR valve assembly	A
Lean	Lean/Rich	Air fuel ratio sensor (sensor 1) malfunction	Air fuel ratio sensor (sensor 1)	B
Rich	Lean/Rich	Air fuel ratio sensor (sensor 1) malfunction	Air fuel ratio sensor (sensor 1)	B
Lean/Rich	Lean	Air fuel ratio sensor (sensor 2) malfunction	Air fuel ratio sensor (sensor 2) Gas leak from exhaust system	C
Lean/Rich	Rich	Air fuel ratio sensor (sensor 2) malfunction	Air fuel ratio sensor (sensor 2) Gas leak from exhaust system	C
Lean	Lean	Actual air fuel ratio lean	Extremely lean actual air fuel ratio Gas leak from exhaust system EGR valve assembly	D
Rich	Rich	Actual air fuel ratio rich	Extremely rich actual air fuel ratio Gas leak from exhaust system EGR valve assembly	D

Lean: During the Control the Injection Volume for A/F Sensor Active Test, the air fuel ratio sensor (sensor 1) output voltages (A/F (O2) Sensor Voltage B1S1 or A/F (O2) Sensor Voltage B2S1) is consistently higher than 3.4 V, and the air fuel ratio sensor (sensor 2) output currents (A/F (O2) Sensor Current B1S2 or A/F (O2) Sensor Current B2S2) is consistently higher than 0.33 mA.
Rich: During the Control the Injection Volume for A/F Sensor Active Test, the A/F (O2) Sensor Voltage B1S1 or A/F (O2) Sensor Voltage B2S1 is consistently below 3.1 V, and the A/F (O2) Sensor Current B1S2 or A/F (O2) Sensor Current B2S2 is consistently below -0.86 mA.
Lean/Rich: During the Control the Injection Volume for A/F Sensor Active Test, the output value of the air fuel ratio sensor (sensor 1) or air fuel ratio sensor (sensor 2) alternate correctly.

Result:

See step 8

Result:

See step 9

Result:

See step 11

Result:

See step 5

CHECK FOR EXHAUST GAS LEAK

Check for exhaust gas leaks.

No gas leaks in exhaust system.

Result

Proceed to
OK
NG

Result:

See step 15

Result:

See step 6

PERFORM ACTIVE TEST USING TECHSTREAM (CONTROL THE EGR STEP POSITION)

Connect the Techstream to the DLC3.
Turn the power switch on (IG).
Turn the Techstream on.

Put the engine in Inspection Mode (2WD for measuring Exhaust Gas).

Powertrain > Hybrid Control > Utility

Tester Display
Inspection Mode

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.

Enter the following menus: Powertrain / Engine / Active Test / Control the EGR Step Position / Data List / Intake Manifold Absolute Pressure and Engine Independent.

Powertrain > Engine > Active Test

Active Test Display
Control the EGR Step Position

Data List Display
Intake Manifold Absolute Pressure
Engine Independent

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.

NOTE:

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.

The value of Intake Manifold Absolute Pressure changes in response to the EGR step position when the value of Engine Independent is "Operate".

Standard

-	Control the EGR Step Position (Active Test)
-	0 Steps	0 to 30 Steps
Intake Manifold Absolute Pressure (Data List)	(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:

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.

Result

Proceed to
OK
NG

Result:

See step 18

Result:

See step 7

INSPECT EGR VALVE ASSEMBLY

Remove the EGR valve assembly.
Refer to REMOVAL [01/2017 - ]

Check if the EGR valve is stuck open.

EGR valve is tightly closed.

HINT:

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

Refer to INITIALIZATION [01/2017 - 09/2018] , or refer to INITIALIZATION [09/2018 - 04/2020]

Result

Proceed to
OK
NG

Result:

See step 18

Result:

REPLACE EGR VALVE ASSEMBLY. Refer to REMOVAL [01/2017 - ]

REPLACE AIR FUEL RATIO SENSOR (SENSOR 1)

Replace the air fuel ratio sensor (sensor 1).

Refer to REMOVAL [01/2017 - ]

HINT:

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

Refer to INITIALIZATION [01/2017 - 09/2018] , or refer to INITIALIZATION [09/2018 - 04/2020]

Result

Proceed to
NEXT

Result:

See step 16

CHECK FOR EXHAUST GAS LEAK

Check for exhaust gas leaks.

No gas leaks in exhaust system.

Result

Proceed to
OK
NG

Result:

See step 15

Result:

See step 10

REPLACE AIR FUEL RATIO SENSOR (SENSOR 2)

Replace the air fuel ratio sensor (sensor 2).

Refer to REMOVAL [01/2017 - ]

HINT:

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

Refer to INITIALIZATION [01/2017 - 09/2018] , or refer to INITIALIZATION [09/2018 - 04/2020]

Result

Proceed to
NEXT

Result:

See step 16

CHECK FOR EXHAUST GAS LEAK

Check for exhaust gas leaks.

No gas leaks in exhaust system.

Result

Proceed to
OK
NG

Result:

See step 15

Result:

See step 12

PERFORM ACTIVE TEST USING TECHSTREAM (CONTROL THE EGR STEP POSITION)

Connect the Techstream to the DLC3.
Turn the power switch on (IG).
Turn the Techstream on.

Put the engine in Inspection Mode (2WD for measuring Exhaust Gas).

Powertrain > Hybrid Control > Utility

Tester Display
Inspection Mode

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.

Enter the following menus: Powertrain / Engine / Active Test / Control the EGR Step Position / Data List / Intake Manifold Absolute Pressure and Engine Independent.

Powertrain > Engine > Active Test

Active Test Display
Control the EGR Step Position

Data List Display
Intake Manifold Absolute Pressure
Engine Independent

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.

NOTE:

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.

The value of Intake Manifold Absolute Pressure changes in response to the EGR step position when the value of Engine Independent is "Operate".

Standard

-	Control the EGR Step Position (Active Test)
-	0 Steps	0 to 30 Steps
Intake Manifold Absolute Pressure (Data List)	(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:

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.

Result

Proceed to
OK
NG

Result:

See step 14

Result:

See step 13

INSPECT EGR VALVE ASSEMBLY

Remove the EGR valve assembly.
Refer to REMOVAL [01/2017 - ]

Check if the EGR valve is stuck open.

EGR valve is tightly closed.

HINT:

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

Refer to INITIALIZATION [01/2017 - 09/2018] , or refer to INITIALIZATION [09/2018 - 04/2020]

Result

Proceed to
OK
NG

Result:

REPLACE EGR VALVE ASSEMBLY. Refer to REMOVAL [01/2017 - ]

Result:

See step 14

CHECK CAUSE OF EXTREMELY RICH OR LEAN ACTUAL AIR FUEL RATIO

Check the cause of extremely rich or lean actual air fuel ratio, referring to the DTC P0171-00, P0172-00, P0174-00 and P0175-00 Inspection Procedure.

Refer to DTC P0171-00: System Too Lean Bank 1; DTC P0172-00: System Too Rich Bank 1; DTC P0174-00: System Too Lean Bank 2; DTC P0175-00: System Too Rich Bank 2; DTC P1170-00: Fuel Performance/Port Injector; DTC P117B-00: Fuel Performance/Direct Injector [01/2017 - 04/2020]

Result

Proceed to
NEXT

Result:

See step 16

REPAIR OR REPLACE EXHAUST SYSTEM

Repair or replace exhaust system.

HINT:

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

Refer to INITIALIZATION [01/2017 - 09/2018] , or refer to INITIALIZATION [09/2018 - 04/2020]

Result

Proceed to
NEXT

Result:

See step 16

CLEAR DTC

Connect the Techstream to the DLC3.
Turn the power switch on (IG).
Turn the Techstream on.
Clear the DTCs.
Powertrain > Engine > Clear DTCs

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

Result

Proceed to
NEXT

Result:

See step 17

CONFIRM WHETHER MALFUNCTION HAS BEEN SUCCESSFULLY REPAIRED

Drive the vehicle in accordance with the driving pattern described in Confirmation Driving Pattern.
Enter the following menus: Powertrain / Engine / Trouble Codes.

Read the DTCs.

Powertrain > Engine > Trouble Codes

Result

Result	Proceed to
DTCs are not output	A
DTC P0420-00 and/or P0430-00 is output	B

Result:

END

Result:

See step 18

CHECK DTC OUTPUT (DTC P0420-00 AND/OR P0430-00)

HINT:

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

Connect the Techstream to the DLC3.
Turn the power switch on (IG).
Turn the Techstream on.
Enter the following menus: Powertrain / Engine / Trouble Codes.

Read the DTCs.

Powertrain > Engine > Trouble Codes

Result

Result	Proceed to
DTC P0420-00 is output	A
DTC P0430-00 is output	B
DTC P0420-00 and P0430-00 are output	C

Result:

REPLACE EXHAUST MANIFOLD ASSEMBLY RH (TWC: FRONT CATALYST AND REAR CATALYST). Refer to REMOVAL [01/2017 - ]

Result:

REPLACE EXHAUST MANIFOLD ASSEMBLY LH (TWC: FRONT CATALYST AND REAR CATALYST). Refer to REMOVAL [01/2017 - ]

Result:

REPLACE EXHAUST MANIFOLD ASSEMBLY RH AND LH (TWC: FRONT CATALYST AND REAR CATALYST). Refer to REMOVAL [01/2017 - ]