DTC P0420: Catalyst System Efficiency Below Threshold (Bank 1); DTC P0430: Catalyst System Efficiency Below Threshold (Bank 2) [10/2015 - 07/2020]: Procedure

1. Connect the Techstream to the DLC3.
2. Turn the power switch on (IG).
3. Turn the Techstream on.
4. Enter the following menus: Powertrain / Engine and ECT / Trouble Codes.
5. Read the DTCs.

   Powertrain > Engine and ECT > Trouble Codes 

   Result

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

   HINT: 

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

Result: 

B 

GO TO DTC CHART. Refer to  DIAGNOSTIC TROUBLE CODE CHART [10/2015 - 08/2016]  , or refer to  DIAGNOSTIC TROUBLE CODE CHART [08/2016 - 12/2017]  , or refer to  DIAGNOSTIC TROUBLE CODE CHART [12/2017 - 03/2018]  , or refer to  DIAGNOSTIC TROUBLE CODE CHART [03/2018 - 08/2018]  , or refer to  DIAGNOSTIC TROUBLE CODE CHART [08/2018 - 08/2019]  , or refer to  DIAGNOSTIC TROUBLE CODE CHART [08/2019 - 07/2020] 

Result: 

A 

See step  2

1. Connect the Techstream to the DLC3.
2. Turn the power switch on (IG).
3. Turn the Techstream on.
4. Put the engine in inspection mode (maintenance mode).

   Powertrain > Hybrid Control > Utility 

   Tester Display
   Inspection Mode

5. Start the engine warm it up.
6. Idle the engine for 5 minutes or more with the shift lever in P.
7. Enter the following menus: Powertrain / Engine and ECT / Active Test / Control the Injection Volume for A/F Sensor / Data List / AFS Voltage B1S1 and O2S B1S2 or AFS Voltage B2S1 and O2S B2S2.

   Powertrain > Engine and ECT > Active Test 

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

   Data List Display
   AFS Voltage B1S1
   AFS Voltage B2S1
   O2S B1S2
   O2S B2S2

8. Perform the Active Test operation with the engine idling (press the 12.5% or -12.5% button to change the fuel injection volume).
9. Monitor the voltage outputs of the air fuel ratio sensor and heated oxygen sensor (AFS Voltage B1S1 and O2S B1S2 or AFS Voltage B2S1 and O2S B2S2) displayed on the Techstream.

   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%.
   • Each sensor reacts in accordance with increases and decreases in the fuel injection volume.
   • 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.
   • If the sensor output voltage does not change (almost no reaction) while performing the Active Test, the sensor may be malfunctioning.

   Standard

   Techstream Display (Sensor)	Injection Volume	Status	Voltage
   AFS Voltage B1S1 AFS Voltage B2S1 (Air fuel ratio)	12.5%	Rich	Below 3.1 V
   	-12.5%	Lean	Higher than 3.4 V
   O2S B1S2 O2S B2S2 (Heated oxygen)	12.5%	Rich	Higher than 0.55 V
   	-12.5%	Lean	Below 0.4 V

   Result

   Status AFS Voltage B1S1 or AFS Voltage B2S1	Status O2S B1S2 or O2S B2S2	Actual air fuel ratio, air fuel ratio sensor and heated oxygen sensor 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 malfunction	Air fuel ratio sensor	B
   Rich	Lean/Rich	Air fuel ratio sensor malfunction	Air fuel ratio sensor
   Lean/Rich	Lean	Heated oxygen sensor malfunction	Heated oxygen sensor Gas leak from exhaust system	C
   Lean/Rich	Rich	Heated oxygen sensor malfunction	Heated oxygen sensor Gas leak from exhaust system
   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

   1. Lean: During Control the Injection Volume for A/F Sensor Active Test, the air fuel ratio sensor output voltage (AFS Voltage B1S1 or AFS Voltage B2S1) is consistently higher than 3.4 V, and the heated oxygen sensor output voltage (O2S B1S2 or O2S B2S2) is consistently below 0.4 V.
   2. Rich: During Control the Injection Volume for A/F Sensor Active Test, AFS Voltage B1S1 or AFS Voltage B2S1 is consistently below 3.1 V, and O2S B1S2 or O2S B2S2 is consistently higher than 0.55 V.
   3. Lean/Rich: During Control the Injection Volume for A/F Sensor Active Test, the output voltage of the air fuel ratio sensor or heated oxygen sensor alternate correctly.

Result: 

B 

See step  6

Result: 

C 

See step  7

Result: 

D 

See step  9

Result: 

A 

See step  3

1. Check for exhaust gas leaks.

   OK

   No gas leaks.

   Result

   Proceed to
   OK
   NG

Result: 

NG 

See step  13

Result: 

OK 

See step  4

1. Connect the Techstream to the DLC3.
2. Turn the power switch on (IG).
3. Turn the Techstream on.
4. Put the engine in inspection mode (maintenance mode).

   Powertrain > Hybrid Control > Utility 

   Tester Display
   Inspection Mode

5. 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.

6. Enter the following menus: Powertrain / Engine and ECT / Active Test / Control the EGR Step Position / Data List / MAP and Throttle Idle Position.

   Powertrain > Engine and ECT > Active Test 

   Active Test Display
   Control the EGR Step Position

   Data List Display
   MAP
   Throttle Idle Position

7. Confirm that the Throttle Idle Position is ON and check the MAP value in the Data List while performing the Active Test.

   HINT: 

   • 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

   MAP change in response to EGR step position when Throttle Idle Position is ON in Data List.

   Standard

   -	EGR Step Position (Active Test)
   	0 Steps	0 to 30 Steps
   MAP (Data List)	(EGR valve is fully closed)	MAP value is at least +10 kPa (1.45 psi) higher than when EGR valve is fully closed

   HINT: 

   • While performing the Active Test, if the increase in the value of MAP is small, the EGR valve assembly may be a malfunctioning.
   • Even if the EGR valve assembly is malfunctioning, rough idling or an increase in the value of MAP may occur while performing the Active Test. However, the amount that the value of MAP increases will be smaller than normal.

   Result

   Proceed to
   OK
   NG

Result: 

OK 

See step  15

Result: 

NG 

See step  5

1. Remove the EGR valve assembly.

   Refer to REMOVAL [10/2015 - ]

2. 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.

   Refer to INITIALIZATION [10/2015 - ]

   Result

   Proceed to
   OK
   NG

Result: 

OK 

See step  15

Result: 

NG 

REPLACE EGR VALVE ASSEMBLY. Refer to  REMOVAL [10/2015 - ] 

1. Replace the air fuel ratio sensor.

   Refer to REMOVAL [10/2015 - ]

   HINT: 

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

   Refer to INITIALIZATION [10/2015 - ]

   Result

   Proceed to
   NEXT

Result: 

NEXT 

See step  14

1. Check for exhaust gas leaks.

   OK

   No gas leaks.

   Result

   Proceed to
   OK
   NG

Result: 

NG 

See step  13

Result: 

OK 

See step  8

1. Replace the heated oxygen sensor.

   Refer to REMOVAL [10/2015 - ]

   HINT: 

   Perform "Inspection After Repair" after replacing the heated oxygen sensor.

   Refer to INITIALIZATION [10/2015 - ]

   Result

   Proceed to
   NEXT

Result: 

NEXT 

See step  14

1. Check for exhaust gas leaks.

   OK

   No gas leaks.

   Result

   Proceed to
   OK
   NG

Result: 

NG 

See step  13

Result: 

OK 

See step  10

1. Connect the Techstream to the DLC3.
2. Turn the power switch on (IG).
3. Turn the Techstream on.
4. Put the engine in inspection mode (maintenance mode).

   Powertrain > Hybrid Control > Utility 

   Tester Display
   Inspection Mode

5. 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.

6. Enter the following menus: Powertrain / Engine and ECT / Active Test / Control the EGR Step Position / Data List / MAP and Throttle Idle Position.

   Powertrain > Engine and ECT > Active Test 

   Active Test Display
   Control the EGR Step Position

   Data List Display
   MAP
   Throttle Idle Position

7. Confirm that the Throttle Idle Position is ON and check the MAP value in the Data List while performing the Active Test.

   HINT: 

   • 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

   MAP change in response to EGR step position when Throttle Idle Position is ON in Data List.

   Standard

   -	EGR Step Position (Active Test)
   	0 Steps	0 to 30 Steps
   MAP (Data List)	(EGR valve is fully closed)	MAP value is at least +10 kPa (1.45 psi) higher than when EGR valve is fully closed

   HINT: 

   • While performing the Active Test, if the increase in the value of MAP is small, the EGR valve assembly may be a malfunctioning.
   • Even if the EGR valve assembly is malfunctioning, rough idling or an increase in the value of MAP may occur while performing the Active Test. However, the amount that the value of MAP increases will be smaller than normal.

   Result

   Proceed to
   OK
   NG

Result: 

OK 

See step  12

Result: 

NG 

See step  11

1. Remove the EGR valve assembly.

   Refer to REMOVAL [10/2015 - ]

2. 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.

   Refer to INITIALIZATION [10/2015 - ]

   Result

   Proceed to
   OK
   NG

Result: 

NG 

REPLACE EGR VALVE ASSEMBLY. Refer to  REMOVAL [10/2015 - ] 

Result: 

OK 

See step  12

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

   Refer to DTC P0171: System Too Lean (Bank 1); DTC P0172: System Too Rich (Bank 1); DTC P0174: System Too Lean (Bank 2); DTC P0175: System Too Rich (Bank 2); DTC P1170: Fuel Performance / Port Injector; DTC P117B: Fuel Performance / Direct Injector [10/2015 - 12/2017] , or refer to DTC P0171: System Too Lean (Bank 1); DTC P0172: System Too Rich (Bank 1); DTC P0174: System Too Lean (Bank 2); DTC P0175: System Too Rich (Bank 2); DTC P1170: Fuel Performance / Port Injector; DTC P117B: Fuel Performance / Direct Injector [12/2017 - 07/2020]

   Result

   Proceed to
   NEXT

Result: 

NEXT 

See step  14

1. Repair or replace exhaust gas leak point.

   HINT: 

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

   Refer to INITIALIZATION [10/2015 - ]

   Result

   Proceed to
   NEXT

Result: 

NEXT 

See step  14

1. Connect the Techstream to the DLC3.
2. Turn the power switch on (IG).
3. Turn the Techstream on.
4. Clear the DTCs.

   Powertrain > Engine and ECT > Clear DTCs 

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. Put the engine in inspection mode (maintenance mode).

   Powertrain > Hybrid Control > Utility 

   Tester Display
   Inspection Mode

9. Start the engine.
10. Drive the vehicle in accordance with the driving pattern described in the Confirmation Driving Pattern.
11. Enter the following menus: Powertrain / Engine and ECT / Trouble Codes.
12. Read the DTCs.

    Powertrain > Engine and ECT > Trouble Codes 

    Result

    Result	Proceed to
    DTCs are not output (Pending DTCs are not output)	A
    DTC P0420 and/or P0430 are output	B

Result: 

A 

END 

Result: 

B 

See step  15

HINT: 

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

1. Connect the Techstream to the DLC3.
2. Turn the power switch on (IG).
3. Turn the Techstream on.
4. Enter the following menus: Powertrain / Engine and ECT / Trouble Codes.
5. Read the DTCs.

   Powertrain > Engine and ECT > Trouble Codes 

   Result

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

Result: 

A 

REPLACE EXHAUST MANIFOLD (TWC: FRONT CATALYST) AND CENTER EXHAUST PIPE ASSEMBLY (TWC: REAR CATALYST) 

Refer to COMPONENTS [10/2015 - ]

Refer to COMPONENTS [10/2015 - 03/2018] , or refer to COMPONENTS [03/2018 - ]

Result: 

B 

REPLACE EXHAUST MANIFOLD ASSEMBLY LH (TWC: FRONT CATALYST) AND CENTER EXHAUST PIPE ASSEMBLY (TWC: REAR CATALYST) 

Refer to COMPONENTS [10/2015 - ]

Refer to COMPONENTS [10/2015 - 03/2018] , or refer to COMPONENTS [03/2018 - ]

Result: 

C 

REPLACE EXHAUST MANIFOLD, EXHAUST MANIFOLD ASSEMBLY LH (TWC: FRONT CATALYST) AND CENTER EXHAUST PIPE ASSEMBLY (TWC: REAR CATALYST) 

Refer to COMPONENTS [10/2015 - ]

Refer to COMPONENTS [10/2015 - 03/2018] , or refer to COMPONENTS [03/2018 - ]