DTC P0420: Catalyst System Efficiency Below Threshold (Bank 1); DTC P0430: Catalyst System Efficiency Below Threshold (Bank 2) [08/2015 - 08/2019]: Procedure

1. Connect the Techstream to the DLC3.
2. Turn the ignition switch to ON.
3. Turn the Techstream on.
4. Enter the following menus: Powertrain / Engine and ECT / Trouble Codes.
5. Read DTCs.
   RESULT
   
   

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

   HINT: 

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

Result: 

B 

GO TO DTC CHART 

Refer to

DIAGNOSTIC TROUBLE CODE CHART [08/2015 - 10/2016] , or refer to

DIAGNOSTIC TROUBLE CODE CHART [10/2016 - 08/2018] , or refer to

DIAGNOSTIC TROUBLE CODE CHART [08/2018 - 08/2019] )

Result: 

A 

See step  2

1. Connect the Techstream to the DLC3.
2. Start the engine.
3. Turn the Techstream on.
4. Warm up the engine and run the engine at an engine speed of 2500 RPM for approximately 90 seconds.
5. Enter the following menus: Powertrain / Engine and ECT / Active Test / Control the Injection Volume for A/F Sensor.
6. Perform the Control the Injection Volume operation with the engine idling.
7. Monitor the voltage outputs of the air fuel ratio and heated oxygen sensors (AFS Voltage B1S1 and O2S B1S2 or AFS Voltage B2S1 and O2S B2S2) displayed on the Techstream.

   HINT: 

   • Change the fuel injection volume within the range of -12.5% to +12.5%.
   • 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.

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

   RESULT
   
   

   Status of AFS Voltage B1S1 or AFS Voltage B2S1	Status of O2S B1S2 or O2S B2S2	Air Fuel Ratio Condition and Air Fuel Ratio and Heated Oxygen Sensor Condition	Suspected Trouble Area	Proceed to
   Lean/Rich	Lean/Rich	Normal	Three-way catalytic converter Gas leaks from exhaust system	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	B
   Lean/Rich	Lean	Heated oxygen sensor malfunction	Heated oxygen sensor Gas leaks from exhaust system	C
   Lean/Rich	Rich	Heated oxygen sensor malfunction	Heated oxygen sensor Gas leaks from exhaust system	C
   Lean	Lean	Actual air fuel ratio lean	Extremely rich or lean actual air fuel ratio Gas leaks from exhaust system	D
   Rich	Rich	Actual air fuel ratio rich	Extremely rich or lean actual air fuel ratio Gas leaks from exhaust system	D

   Lean: During the Control the Injection Volume Active Test, the air fuel ratio sensor output voltage (AFS Voltage) is consistently higher than 3.4 V, and the heated oxygen sensor output voltage (O2S) is consistently below 0.4 V.

   Rich: During the Control the Injection Volume Active Test, the AFS Voltage is consistently below 3.1 V, and the O2S is consistently higher than 0.55 V.

   Lean/Rich: During the Control the Injection Volume Active Test, the output voltage of the air fuel ratio sensor and heated oxygen sensor alternate correctly.

8. Refer to "Data List / Active Test" [AFS Voltage B1S1, AFS Voltage B2S1, O2S B1S2 and O2S B2S2]. Refer to

   DATA LIST / ACTIVE TEST [08/2015 - 08/2017] , or refer to

   DATA LIST / ACTIVE TEST [08/2017 - 08/2018] , or refer to

   DATA LIST / ACTIVE TEST [08/2018 - 08/2019]

Result: 

B 

REPLACE AIR FUEL RATIO SENSOR 

(Refer to REMOVAL [08/2015 - ] )

Result: 

C 

See step  5

Result: 

D 

See step  6

Result: 

A 

See step  3

1. Check for exhaust gas leaks from the exhaust manifold sub-assembly and exhaust pipes.

   OK

   No gas leaks.

   HINT: 

   Perform "Inspection After Repair" after repairing or replacing the exhaust system (Refer to INITIALIZATION [08/2015 - 08/2019] ).

Result: 

NG 

REPAIR OR REPLACE FOR EXHAUST GAS LEAK POINT 

Result: 

OK 

See step  4

1. Connect the Techstream to the DLC3.
2. Turn the ignition switch to ON.
3. Turn the Techstream on.
4. Clear the DTCs.
5. Turn the ignition switch off and wait for at least 30 seconds.
6. Turn the ignition switch to ON.
7. Turn the Techstream on.
8. Start the engine.
9. Drive the vehicle in accordance with the driving pattern described in Confirmation Driving Pattern.
10. Enter the following menus: Powertrain / Engine and ECT / Trouble Codes.
11. Read the DTCs.
    RESULT
    
    

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

Result: 

A 

REPLACE FRONT NO. 2 EXHAUST PIPE ASSEMBLY (TWC: FRONT CATALYST AND REAR CATALYST) 

(Refer to COMPONENTS [08/2015 - 08/2019] )

Result: 

B 

REPLACE FRONT NO. 2 EXHAUST PIPE ASSEMBLY (TWC: FRONT CATALYST AND REAR CATALYST) 

(Refer to COMPONENTS [08/2015 - 08/2019] )

1. Check for exhaust gas leaks from the exhaust manifold assembly and exhaust pipes.

   OK

   No gas leaks.

   HINT: 

   • Perform "Inspection After Repair" after repairing or replacing the exhaust system (Refer to INITIALIZATION [08/2015 - 08/2019] ).
   • Perform "Inspection After Repair" after replacing the heated oxygen sensor (Refer to INITIALIZATION [08/2015 - 08/2019] ).

Result: 

OK 

REPLACE HEATED OXYGEN SENSOR 

(Refer to REMOVAL [08/2015 - ] )

Result: 

NG 

REPAIR OR REPLACE EXHAUST GAS LEAK POINT 

1. Check for exhaust gas leaks from the exhaust manifold assembly and exhaust pipes.

   OK

   No gas leaks.

   HINT: 

   Perform "Inspection After Repair" after repairing or replacing the exhaust system (Refer to INITIALIZATION [08/2015 - 08/2019] ).

Result: 

OK 

CHECK CAUSE OF EXTREMELY RICH OR LEAN ACTUAL AIR-FUEL RATIO 

Result: 

NG 

REPAIR OR REPLACE EXHAUST GAS LEAK POINT