DTC P0420: Catalyst System Efficiency Below Threshold (Bank 1); DTC P0430: Catalyst System Efficiency Below Threshold (Bank 2) [09/2014 - 10/2015]: Procedure

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

   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 or P0430 are output, troubleshoot those DTCs first.

Result: 

B 

GO TO DTC CHART 

(Refer to DIAGNOSTIC TROUBLE CODE CHART [09/2014 - 10/2015] )

Result: 

A 

See step  2

1. Connect the Techstream to the DLC3.
2. Start the engine and warm it up.
3. Turn the Techstream on.
4. 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 / AFS Voltage B1S1 and O2S B1S2 or AFS Voltage B2S1 and O2S B2S2.
6. Perform the Active Test operation with the engine idling (press the RIGHT or LEFT button to change the fuel injection volume).
7. 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: 

   • Change the fuel injection volume within the range of - 12.5% to +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 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 AFS Voltage B1S1 or AFS Voltage B2S1	Status O2S B1S2 or O2S B2S2	A/F Condition and A/F and HO2 Sensor Conditions	Misfire	Main Suspected Trouble Areas	Proceed to
   Lean/Rich	Lean/Rich	Normal	-	Three-Way Catalytic Converter (TWC) Gas leakage 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	May occur	Air fuel ratio sensor
   Lean/Rich	Lean	Heated oxygen sensor malfunction	-	Heated oxygen sensor Gas leakage from exhaust system	C
   Lean/Rich	Rich	Heated oxygen sensor malfunction	-	Heated oxygen sensor Gas leakage from exhaust system
   Lean	Lean	Actual air-fuel ratio lean	May occur	Extremely rich or lean actual air-fuel ratio Gas leakage from exhaust system	D
   Rich	Rich	Actual air-fuel ratio lean	-	Extremely rich or lean actual air-fuel ratio Gas leakage from exhaust system

   Lean: During Control the Injection Volume for A/F Sensor, 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.

   Rich: During Control the Injection Volume for A/F Sensor, the AFS Voltage B1S1 or AFS Voltage B2S1 is consistently below 3.1 V, and the O2S B1S2 or O2S B2S2 is consistently higher than 0.55 V.

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

Result: 

B 

See step  7

Result: 

C 

See step  5

Result: 

D 

See step  6

Result: 

A 

See step  3

1. Check for exhaust gas leaks.

   OK

   No gas leaks.

Result: 

NG 

See step  8

Result: 

OK 

See step  4

HINT: 

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

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

   Result

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

Result: 

C 

REPLACE FRONT EXHAUST PIPE ASSEMBLY (TWC: REAR CATALYST) 

(Refer to REMOVAL [09/2014 - 10/2015] )

Result: 

A 

REPLACE EXHAUST MANIFOLD SUB-ASSEMBLY RH (TWC: FRONT CATALYST) 

(Refer to REMOVAL [09/2014 - 10/2015] )

Result: 

B 

REPLACE EXHAUST MANIFOLD SUB-ASSEMBLY LH (TWC: FRONT CATALYST) 

(Refer to REMOVAL [09/2014 - 10/2015] )

1. Check for exhaust gas leaks.

   OK

   No gas leaks.

Result: 

OK 

See step  9

Result: 

NG 

See step  8

1. Check for exhaust gas leaks.

   OK

   No gas leaks.

Result: 

OK 

See step  10

Result: 

NG 

See step  8

1. Replace the air fuel ratio sensor (Refer to REMOVAL [09/2014 - 10/2015] ).

   HINT: 

   Perform "Inspection After Repair" after replacing the air fuel ratio sensor (Refer to INITIALIZATION [09/2014 - 10/2015] ).

Result: 

NEXT 

See step  11

1. Repair or replace exhaust gas leak point.

   HINT: 

   Perform "Inspection After Repair" after repairing or replacing the exhaust system (Refer to INITIALIZATION [09/2014 - 10/2015] ).

Result: 

NEXT 

See step  11

1. Replace the heated oxygen sensor (Refer to REMOVAL [09/2014 - 10/2015] ).

   HINT: 

   Perform "Inspection After Repair" after repairing or replacing the heated oxygen sensor (Refer to INITIALIZATION [09/2014 - 10/2015] ).

Result: 

NEXT 

See step  11

1. Check the cause of extremely rich or lean actual air fuel ratio, referring to the DTC P0171 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: Port Injector Fuel Performance; DTC P117B: Direct Injector Fuel Performance [09/2014 - 10/2015] ).

Result: 

NEXT 

See step  11

1. Connect the Techstream to the DLC3.
2. Turn the engine switch on (IG).
3. Turn the Techstream on.
4. Clear the DTCs (Refer to DTC CHECK / CLEAR [09/2014 - 10/2015] ).
5. Turn the engine switch off and wait for at least 30 seconds.
6. Start the engine.
7. Turn the Techstream on.
8. Drive the vehicle in accordance with the driving pattern described in Confirmation Driving Pattern.
9. Enter the following menus: Powertrain / Engine and ECT / Trouble Codes.
10. Read the pending DTCs.

    Result

    Result	Proceed to
    DTC P0420 and/or P0430 is output	A
    DTC is not output	B

Result: 

B 

END 

Result: 

A 

See step  12

HINT: 

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

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

   Result

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

Result: 

C 

REPLACE FRONT EXHAUST PIPE ASSEMBLY (TWC: REAR CATALYST) 

(Refer to REMOVAL [09/2014 - 10/2015] )

Result: 

A 

REPLACE EXHAUST MANIFOLD SUB-ASSEMBLY RH (TWC: FRONT CATALYST) 

(Refer to REMOVAL [09/2014 - 10/2015] )

Result: 

B 

REPLACE EXHAUST MANIFOLD SUB-ASSEMBLY LH (TWC: FRONT CATALYST) 

(Refer to REMOVAL [09/2014 - 10/2015] )