DTC P0420-00: Catalyst System Efficiency Below Threshold Bank 1 [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 / Trouble Codes.
5. Read the DTCs.

   Result

   Result	Proceed to
   DTC P042000 is output	A
   DTC P042000 and other DTCs are output	B

   HINT: 

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

Result: 

B 

GO TO DTC CHART. Refer to  DIAGNOSTIC TROUBLE CODE CHART [10/2015 - 09/2016]  , or refer to  DIAGNOSTIC TROUBLE CODE CHART [09/2016 - 09/2017]  , or refer to  DIAGNOSTIC TROUBLE CODE CHART [09/2017 - 09/2018]  , or refer to  DIAGNOSTIC TROUBLE CODE CHART [09/2018 - ] 

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 / Active Test / Control the Injection Volume for A/F Sensor / Data List / A/F (O2) Sensor Voltage B1S1 and O2 Sensor Voltage B1S2.
6. Perform the Active Test operation with the engine idling (change the fuel injection volume).
7. Monitor the voltage outputs of the air fuel ratio sensor and heated oxygen sensor (A/F (O2) Sensor Voltage B1S1 and O2 Sensor Voltage B1S2) 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
   A/F (O2) Sensor Voltage B1S1 (Air fuel ratio)	+12.5%	Rich	Below 3.1 V
   	-12.5%	Lean	Higher than 3.4 V
   O2 Sensor Voltage B1S2 (Heated oxygen)	+12.5%	Rich	Higher than 0.55 V
   	-12.5%	Lean	Below 0.4 V

   Result

   Status A/F (O2) Sensor Voltage B1S1	Status O2 Sensor Voltage B1S2	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	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 rich or lean actual air fuel ratio Gas leak from exhaust system	D
   Rich	Rich	Actual air fuel ratio rich	Extremely rich or lean actual air fuel ratio Gas leak from exhaust system

   • Lean: During Control the Injection Volume for A/F Sensor, the air fuel ratio sensor output voltage (A/F (O2) Sensor Voltage B1S1) is consistently higher than 3.4 V, and the heated oxygen sensor output voltage (O2 Sensor Voltage B1S2) is consistently less than 0.4 V.
   • Rich: During Control the Injection Volume for A/F Sensor, the A/F (O2) Sensor Voltage B1S1 is consistently less than 3.1 V, and the O2 Sensor Voltage B1S2 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 alternates correctly.

Result: 

B 

See step  4

Result: 

C 

See step  5

Result: 

D 

See step  7

Result: 

A 

See step  3

1. Check for exhaust gas leaks.

   OK

   No gas leaks.

   Result

   Proceed to
   OK
   NG

Result: 

OK 

See step  11

Result: 

NG 

See step  9

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 - 09/2018] , or refer to INITIALIZATION [09/2018 - ]

   Result

   Proceed to
   NEXT

Result: 

NEXT 

See step  10

1. Check for exhaust gas leaks.

   OK

   No gas leaks.

   Result

   Proceed to
   OK
   NG

Result: 

NG 

See step  9

Result: 

OK 

See step  6

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 - 09/2018] , or refer to INITIALIZATION [09/2018 - ]

   Result

   Proceed to
   NEXT

Result: 

NEXT 

See step  10

1. Check the exhaust gas leaks.

   OK

   No gas leaks.

   Result

   Proceed to
   OK
   NG

Result: 

NG 

See step  9

Result: 

OK 

See step  8

1. Check the cause of extremely rich or lean actual air fuel ratio, referring to the DTC P017100 Inspection Procedure.

   Refer to DTC P0171-00: System Too Lean Bank 1; DTC P017200: System Too Rich Bank 1; DTC P117000: Fuel Performance/Port Injector; DTC P117B00: Fuel Performance/Direct Injector [10/2015 - 09/2018] , or refer to DTC P0171-00: System Too Lean Bank 1; DTC P017200: System Too Rich Bank 1; DTC P117000: Fuel Performance/Port Injector; DTC P117B00: Fuel Performance/Direct Injector [09/2018 - ]

   Result

   Proceed to
   NEXT

Result: 

NEXT 

See step  10

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 - 09/2018] , or refer to INITIALIZATION [09/2018 - ]

   Result

   Proceed to
   NEXT

Result: 

NEXT 

See step  10

1. Connect the Techstream to the DLC3.
2. Turn the engine switch on (IG).
3. Turn the Techstream on.
4. Clear the DTCs.
5. Turn the engine switch off and wait for at least 30 seconds.
6. Turn the engine switch on (IG).
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 / Trouble Codes.
11. Read the DTCs.

    Result

    Result	Proceed to
    DTC P042000 is output	A
    DTCs are not output (No pending DTCs output)	B

Result: 

B 

END 

Result: 

A 

See step  11

HINT: 

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

1. Replace the exhaust manifold converter sub-assembly (TWC: Front and rear catalyst).

   Refer to COMPONENTS [10/2015 - ]

   Result

   Proceed to
   NEXT

Result: 

NEXT 

END