DTC P0420-00: Catalyst System Efficiency Below Threshold Bank 1; DTC P0430-00: Catalyst System Efficiency Below Threshold Bank 2 [10/2023 - ]: Procedure

1. Read the DTCs.

   Powertrain > Engine > Trouble Codes 

   Result

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

   HINT: 

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

Result: 

A 

GO TO DTC CHART. Refer to  DIAGNOSTIC TROUBLE CODE CHART [10/2023 - ] 

Result: 

B 

See step  2

1. Using the GTS, read the value displayed in the Freeze Frame Data.

   Refer to FREEZE FRAME DATA [12/2021 - ]

   Result

   GTS Display	Result	Proceed to
   Long FT B1S2 Long FT B2S2	Less than 1.0%	A
   	1.0% or higher	B

Result: 

B 

See step  49

Result: 

A 

See step  3

Pre-procedure1

• Start the engine and warm it up until the engine coolant temperature is 75°C (167°F) or higher.
• Warm up the air fuel ratio sensors at an engine speed of 2500 rpm for 90 seconds.

• Change the fuel injection volume using the GTS, and monitor the output current of the air fuel ratio sensor (sensor 1) (A/F (O2) Sensor Current B1S1 or A/F (O2) Sensor Current B2S1) and air fuel ratio sensor (sensor 2) (A/F (O2) Sensor Current B1S2 or A/F (O2) Sensor Current B2S2) displayed on the GTS.

  Powertrain > Engine > Active Test 

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

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

  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) is displayed as A/F (O2) Sensor Current B1S1 or A/F (O2) Sensor Current B2S1, and the air fuel ratio sensor (sensor 2) is displayed as A/F (O2) Sensor Current B1S2 or A/F (O2) Sensor Current B2S2 on the GTS.
  • 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 current does not change (almost no reaction) while performing the Active Test, the sensor may be malfunctioning.

  Standard

  GTS Display (Sensor)	Injection Volume	Status	Current
  A/F (O2) Sensor Current B1S1 A/F (O2) Sensor Current B2S1 (Air fuel ratio (sensor 1))	12.5%	Rich	Below -0.075 mA
  	-12.5%	Lean	More than 0.037 mA
  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	More than 0.33 mA

  Result

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

  1. Lean: During the Control the Injection Volume for A/F Sensor Active Test, the air fuel ratio sensor (sensor 1) output current (A/F (O2) Sensor Current B1S1 or A/F (O2) Sensor Current B2S1) is consistently more than 0.037 mA, and the air fuel ratio sensor (sensor 2) output current (A/F (O2) Sensor Current B1S2 or A/F (O2) Sensor Current B2S2) is consistently more than 0.33 mA.
  2. Rich: During the Control the Injection Volume for A/F Sensor Active Test, the air fuel ratio sensor (sensor 1) output current (A/F (O2) Sensor Current B1S1 or A/F (O2) Sensor Current B2S1) is consistently below -0.075 mA, and the air fuel ratio sensor (sensor 2) output current (A/F (O2) Sensor Current B1S2 or A/F (O2) Sensor Current B2S2) is consistently below -0.86 mA.
  3. Lean/Rich: During the Control the Injection Volume for A/F Sensor Active Test, the output current of the air fuel ratio sensor (sensor 1) or air fuel ratio sensor (sensor 2) alternate correctly.

  HINT: 

  Refer to "Data List / Active Test" [A/F (O2) Sensor Current B1S1, A/F (O2) Sensor Current B2S1, A/F (O2) Sensor Current B1S2, A/F (O2) Sensor Current B2S2].

  Refer to DATA LIST / ACTIVE TEST [12/2021 - ]

Post-procedure1

• None

Result: 

B 

See step  5

Result: 

C 

See step  6

Result: 

D 

See step  8

Result: 

A 

See step  4

1. Check for exhaust gas leaks.

   OK

   No gas leaks in exhaust system.

   Result

   Proceed to
   OK
   NG

Result: 

OK 

See step  48

Result: 

NG 

See step  45

HINT: 

Refer to REMOVAL [12/2021 - ]

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

Refer to INITIALIZATION [12/2021 - ]

Result

Result: 

NEXT 

See step  46

1. Check for exhaust gas leaks.

   OK

   No gas leaks in exhaust system.

   Result

   Proceed to
   OK
   NG

Result: 

NG 

See step  45

Result: 

OK 

See step  7

HINT: 

Refer to REMOVAL [12/2021 - ]

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

Refer to INITIALIZATION [12/2021 - ]

Result

Result: 

NEXT 

See step  46

1. Check for exhaust gas leaks.

   OK

   No gas leaks in exhaust system.

   Result

   Proceed to
   OK
   NG

Result: 

NG 

See step  45

Result: 

OK 

See step  9

Pre-procedure1

• Start the engine and warm it up until the engine coolant temperature is 75°C (167°F) or higher with all the accessories switched off.

• According to the display on the GTS, read the Data List with the Active Test "Control the Injection Mode" set to Port.

  Powertrain > Engine > Active Test 

  Active Test Display
  Control the Injection Mode

  Data List Display
  Injection Mode
  Short FT B1S1
  Short FT B2S1
  Long FT B1S1
  Long FT B2S1

  OK

  GTS Display	Specified Condition
  Total of Short FT B1S1 and Long FT B1S1	Between -20 and 20%
  Total of Short FT B2S1 and Long FT B2S1

• According to the display on the GTS, read the Data List with the Active Test "Control the Injection Mode" set to Direct.

  OK

  GTS Display	Specified Condition
  Total of Short FT B1S1 and Long FT B1S1	Between -20 and 20%
  Total of Short FT B2S1 and Long FT B2S1

  Result

  Item		Proceed to
  Port	Direct
  OK	OK	A
  OK	NG	B
  NG	OK	C
  NG	NG	D

Post-procedure1

• None

Result: 

B 

See step  11

Result: 

C 

See step  18

Result: 

D 

See step  19

Result: 

A 

See step  10

1. Has the vehicle run out of fuel in the past?

   Result

   Proceed to
   YES
   NO

Result: 

YES 

DTC CAUSED BY RUNNING OUT OF FUEL 

Result: 

NO 

See step  46

Pre-procedure1

• Start the engine and warm it up until the engine coolant temperature is 75°C (167°F) or higher with all the accessories switched off.

• According to the display on the GTS, read the Data List with the following condition.
  • Shift position: P
  • A/C: Off
  • Engine warmed up
  • Engine Speed: 3000 rpm
  • Injection Mode: Direct

  Powertrain > Engine > Data List 

  Tester Display
  Engine Speed
  Fuel Pressure (High)
  Injection Mode

  Result

  Result	Proceed to
  The value of Fuel Pressure (High) is between 2800 and 20000 kPag	A
  None of the above conditions are met	B

Post-procedure1

• None

Result: 

B 

See step  14

Result: 

A 

See step  12

Pre-procedure1

• Start the engine and warm it up until the engine coolant temperature is 75°C (167°F) or higher.

• According to the display on the GTS, read the Data List with the Active Test "Control the Injection Mode" set to Direct.

  Powertrain > Engine > Active Test 

  Active Test Display
  Control the Injection Mode

  Data List Display
  High Pressure Fuel Pump Duty Ratio (D4)
  Injection Mode
  Short FT B1S1
  Short FT B2S1
  Long FT B1S1
  Long FT B2S1

  Result

  Item				Proceed to
  Injection Mode	High Pressure Fuel Pump Duty Ratio (D4)	Total of Short FT B1S1 and Long FT B1S1	Total of Short FT B2S1 and Long FT B2S1
  Direct	10% to 40%	-	-	A
  	40% or higher	-20% or less	-20% or less	B
  	10% or less	+20% or higher	+20% or higher
  	40% or higher	+20% or higher	+20% or higher	C
  	10% or less	-20% or less	-20% or less	D

  HINT: 

  Perform "Inspection After Repair" after replacing the fuel pressure sensor (for high pressure side).

  Refer to INITIALIZATION [12/2021 - ]

Post-procedure1

• None

Result: 

B 

REPLACE FUEL PRESSURE SENSOR (FOR HIGH PRESSURE SIDE). Refer to  REMOVAL [12/2021 - ] 

Result: 

C 

See step  15

Result: 

D 

REPLACE ECM. Refer to  REMOVAL [12/2021 - ] 

Result: 

A 

See step  13

Pre-procedure1

• Start the engine and warm it up until the engine coolant temperature is 75°C (167°F) or higher.

• According to the display on the GTS, read the Data List with the Active Test "Control the Injection Mode" set to Direct.

  Powertrain > Engine > Active Test 

  Active Test Display
  Control the Injection Mode

  Data List Display
  High Pressure Fuel Pump Duty Ratio (D4)
  Injection Mode
  Short FT B1S1
  Short FT B2S1
  Long FT B1S1
  Long FT B2S1

  Result

  Item				Proceed to
  Injection Mode	High Pressure Fuel Pump Duty Ratio (D4)	Total of Short FT B1S1 and Long FT B1S1	Total of Short FT B2S1 and Long FT B2S1
  Direct	10 to 40%	-25% or less	-25% or less	A
  	10 to 40%	+30% or higher	+30% or higher
  	10 to 40%	+25% or higher	-25 to +25%	B
  	10 to 40%	+25% or higher	-25 to +25%
  	10 to 40%	-25 to +25%	-25% or less	C
  	10 to 40%	-25 to +25%	+25% or higher
  	10 to 40%	-25 to +25%	-25 to +25%	D

  HINT: 

  Perform "Inspection After Repair" after replacing the direct fuel injector assembly.

  Refer to INITIALIZATION [12/2021 - ]

Post-procedure1

• None

Result: 

A 

REPLACE DIRECT FUEL INJECTOR ASSEMBLY (ALL CYLINDERS). Refer to  REMOVAL [12/2021 - ] 

Result: 

B 

REPLACE DIRECT FUEL INJECTOR ASSEMBLY (BANK 1). Refer to  REMOVAL [12/2021 - ] 

Result: 

C 

REPLACE DIRECT FUEL INJECTOR ASSEMBLY (BANK 2). Refer to  REMOVAL [12/2021 - ] 

Result: 

D 

CHECK FOR INTERMITTENT PROBLEMS. Refer to  HOW TO PROCEED WITH TROUBLESHOOTING [12/2021 - ] 

Pre-procedure1

• Start the engine and warm it up until the engine coolant temperature is 75°C (167°F) or higher.

• According to the display on the GTS, read the Data List with the Active Test "Control the Injection Mode" set to Direct.

  Powertrain > Engine > Active Test 

  Active Test Display
  Control the Injection Mode

  Data List Display
  Injection Mode
  Misfire Count Cylinder #1
  Misfire Count Cylinder #2
  Misfire Count Cylinder #3
  Misfire Count Cylinder #4
  Misfire Count Cylinder #5
  Misfire Count Cylinder #6

  Result

  Injection Mode	Misfire Count	Proceed to
  Direct	No misfire counts, or misfire counts occur randomly in all cylinders	A
  	Misfire counts occur in particular cylinder	B

  HINT: 

  Perform "Inspection After Repair" after replacing the direct fuel injector assembly.

  Refer to INITIALIZATION [12/2021 - ]

Post-procedure1

• None

Result: 

B 

REPLACE DIRECT FUEL INJECTOR ASSEMBLY. Refer to  REMOVAL [12/2021 - ] 

Result: 

A 

See step  15

HINT: 

Refer to REMOVAL [12/2021 - ]

Perform "Inspection After Repair" after replacing the fuel pump assembly (for high pressure side).

Refer to INITIALIZATION [12/2021 - ]

Result

Result: 

NEXT 

See step  16

Pre-procedure1

• None

• Clear the DTCs.

  Powertrain > Engine > Clear DTCs 

  Result

  Proceed to
  NEXT

Post-procedure1

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

Result: 

NEXT 

See step  17

Pre-procedure1

• Drive the vehicle in accordance with the driving pattern described in Confirmation Driving Pattern.

• Read the DTCs.

  Powertrain > Engine > Trouble Codes 

  Result

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

Post-procedure1

• None

Result: 

A 

END 

Result: 

B 

REPLACE ECM. Refer to  REMOVAL [12/2021 - ] 

1. Check the injection volume (whether fuel volume is high or low, and whether injection pattern is poor).

   Refer to INSPECTION [12/2021 - ]

   HINT: 

   Perform "Inspection After Repair" after replacing the port fuel injector assembly.

   Refer to INITIALIZATION [12/2021 - ]

   Result

   Proceed to
   OK
   NG

Result: 

OK 

REPLACE ECM. Refer to  REMOVAL [12/2021 - ] 

Result: 

NG 

REPLACE PORT FUEL INJECTOR ASSEMBLY. Refer to  REMOVAL [12/2021 - ] 

Refer to INSPECTION [12/2021 - ]

Result

Result: 

NG 

REPLACE PURGE VSV (DUTY VACUUM SWITCHING VALVE). Refer to  REMOVAL [12/2021 - ] 

Result: 

OK 

See step  20

Pre-procedure1

• Disconnect the purge VSV connector.
• Disconnect the ECM connector.

• Measure the resistance according to the value(s) in the table below.

  Standard Resistance

  Tester Connection	Condition	Specified Condition
  C44-2 (PRG) - C37-40 (PRG)	Always	Below 1 Ω
  C44-2 (PRG) or C37-40 (PRG) - Body ground and other terminals	Always	10 kΩ or higher

  Result

  Proceed to
  OK
  NG

Post-procedure1

• None

Result: 

NG 

REPAIR OR REPLACE HARNESS OR CONNECTOR 

Result: 

OK 

See step  21

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

1. Check the PCV hose connections.
2. Check the PCV valve.

   Refer to ON-VEHICLE INSPECTION [12/2021 - ]

   OK

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

   Result

   Proceed to
   OK
   NG

Result: 

NG 

REPAIR OR REPLACE PCV VALVE OR HOSE 

Result: 

OK 

See step  22

1. Check the intake system for vacuum leaks.

   Refer to ON-VEHICLE INSPECTION [12/2021 - ]

   OK

   No leaks in intake system.

   HINT: 

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

   Refer to INITIALIZATION [12/2021 - ]

   Result

   Proceed to
   OK
   NG

Result: 

NG 

REPAIR OR REPLACE INTAKE SYSTEM 

Result: 

OK 

See step  23

Pre-procedure1

• Start the engine and warm it up until the engine coolant temperature reaches 75°C (167°F) or higher.
• Warm up the air fuel ratio sensors at an engine speed of 2500 rpm for 90 seconds.

• Perform the Control the Injection Volume for A/F Sensor operation with the engine idling.

  Powertrain > Engine > Active Test 

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

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

• Monitor the output values of the air fuel ratio sensor (sensor 1) and air fuel ratio sensor (sensor 2) (A/F (O2) Sensor Current B1S1 and A/F (O2) Sensor Current B1S2 or A/F (O2) Sensor Current B2S1 and A/F (O2) Sensor Current B2S2) displayed on the GTS.

  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%.
  • 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

  GTS Display (Sensor)	Injection Volume	Status	Current
  A/F (O2) Sensor Current B1S1 A/F (O2) Sensor Current B2S1 (Air fuel ratio [sensor 1])	12.5%	Rich	Below -0.075 mA
  	-12.5%	Lean	More than 0.037 mA
  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	More than 0.33 mA

  Result

  Status of A/F (O2) Sensor Current B1S1 or A/F (O2) Sensor Current B2S1	Status of A/F (O2) Sensor Current B1S2 or A/F (O2) Sensor Current B2S2	Air Fuel Ratio Condition and Air Fuel Ratio Sensor Condition	Suspected Trouble Area	Proceed to
  Lean/Rich	Lean/Rich	Normal	-	A
  Lean	Lean	Actual air fuel ratio lean	PCV valve and hose PCV hose connections Gas leak from exhaust system Intake system Fuel pressure Mass air flow meter sub-assembly Engine coolant temperature sensor
  Rich	Rich	Actual air fuel ratio rich	Gas leak from exhaust system Ignition system Fuel pressure Mass air flow meter sub-assembly Engine coolant temperature sensor
  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)

  1. Lean: During the Control the Injection Volume for A/F Sensor Active Test, the air fuel ratio sensor (sensor 1) output current (A/F (O2) Sensor Current B1S1 or A/F (O2) Sensor Current B2S1) is consistently more than 0.037 mA, and the air fuel ratio sensor (sensor 2) output current (A/F (O2) Sensor Current B1S2 or A/F (O2) Sensor Current B2S2) is consistently more than 0.33 mA.
  2. Rich: During the Control the Injection Volume for A/F Sensor Active Test, the air fuel ratio sensor (sensor 1) output current (A/F (O2) Sensor Current B1S1 or A/F (O2) Sensor Current B2S1) is consistently below -0.075 mA, and the air fuel ratio sensor (sensor 2) output current (A/F (O2) Sensor Current B1S2 or A/F (O2) Sensor Current B2S2) is consistently below -0.86 mA.
  3. Lean/Rich: During the Control the Injection Volume for A/F Sensor Active Test, the output current of the air fuel ratio sensor (sensor 1) or air fuel ratio sensor (sensor 2) alternate correctly.

  HINT: 

  Refer to "Data List / Active Test" [A/F (O2) Sensor Current B1S1, A/F (O2) Sensor Current B1S2, A/F (O2) Sensor Current B2S1 and A/F (O2) Sensor Current B2S2].

  Refer to DATA LIST / ACTIVE TEST [12/2021 - ]

Post-procedure1

• None

Result: 

B 

See step  30

Result: 

A 

See step  24

1. Read the Data List twice, when the engine is both cold and warmed up.

   Powertrain > Engine > Data List 

   Tester Display
   Coolant Temperature

   Standard

   GTS Display	Condition	Specified Condition
   Coolant Temperature	Cold engine	Same as ambient air temperature
   	Warm engine	Between 75 and 100°C (167 and 212°F)

   HINT: 

   Perform "Inspection After Repair" after replacing the engine coolant temperature sensor.

   Refer to INITIALIZATION [12/2021 - ]

   Result

   Proceed to
   OK
   NG

Result: 

NG 

REPLACE ENGINE COOLANT TEMPERATURE SENSOR. Refer to  REMOVAL [12/2021 - ] 

Result: 

OK 

See step  25

Pre-procedure1

• Start the engine.
• Allow the engine to idle until Coolant Temperature reaches 75°C (167°F) or higher with all the accessories switched off and the shift lever in N.

• Read Mass Air Flow Sensor while maintaining an engine speed of 3000 rpm.

  Powertrain > Engine > Data List 

  Tester Display
  Engine Speed
  MAF Sensor Bank1
  MAF Sensor Bank2

  Result

  Result	Proceed to
  The value of MAF Sensor Bank1 is between 6.5 and 30.0 gm/sec and the value of MAF Sensor Bank2 is between 6.5 and 30.0 gm/sec	A
  None of the above conditions are met	B

Post-procedure1

• None

Result: 

B 

See step  37

Result: 

A 

See step  26

Refer to PROCEDURE - Step 2

Result

Result: 

NG 

See step  29

Result: 

OK 

See step  27

Refer to PROCEDURE - Step 3

HINT: 

Perform "Inspection After Repair" after replacing the spark plug.

Refer to INITIALIZATION [12/2021 - ]

Result

Result: 

NG 

REPLACE SPARK PLUG. Refer to  REMOVAL [12/2021 - ] 

Result: 

OK 

See step  28

Refer to PROCEDURE - Step 1

HINT: 

• If the result of the spark test is normal, proceed to the next step.
• Perform "Inspection After Repair" after replacing the spark plug or ignition coil assembly.

  Refer to INITIALIZATION [12/2021 - ]

Result

Result: 

NEXT 

See step  37

1. Check the fuel lines for leaks or blockage.

   Result

   Proceed to
   OK
   NG

Result: 

OK 

GO TO FUEL PUMP CONTROL CIRCUIT. Refer to  Fuel Pump Control Circuit [12/2021 - ] 

Result: 

NG 

REPAIR OR REPLACE FUEL SYSTEM 

Refer to INSPECTION [12/2021 - ]

HINT: 

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

Refer to INITIALIZATION [12/2021 - ]

Result

Result: 

NG 

REPLACE AIR FUEL RATIO SENSOR (SENSOR 1). Refer to  REMOVAL [12/2021 - ] 

Result: 

OK 

See step  31

Pre-procedure1

• Disconnect the air fuel ratio sensor (sensor 1) connector.
• Turn the ignition switch to ON.

• Measure the voltage according to the value(s) in the table below.

  Standard Voltage

  Tester Connection	Condition	Specified Condition
  C29-2 (+B) - Body ground	Ignition switch ON	11 to 14 V
  C30-2 (+B) - Body ground	Ignition switch ON	11 to 14 V

  Result

  Proceed to
  OK
  NG

Post-procedure1

• None

Result: 

NG 

REPAIR OR REPLACE AIR FUEL RATIO SENSOR (SENSOR 1) POWER SOURCE CIRCUIT. Refer to  DTC P0030-12: HO2S Heater Control Bank 1 Sensor 1 Circuit Short to Battery; DTC P0030-13: HO2S Heater Control Bank 1 Sensor 1 Circuit Open; DTC P0050-12: HO2S Heater Control Bank 2 Sensor 1 Circuit Short to Battery; DTC P0050-13: HO2S Heater Control Bank 2 Sensor 1 Circuit Open; DTC P101A-9E: A/F Sensor Heater Performance Bank 1 Sensor 1 Stuck On; DTC P103A-9E: A/F Sensor Heater Performance Bank 2 Sensor 1 Stuck On [12/2021 - ] 

Result: 

OK 

See step  32

Pre-procedure1

• Disconnect the air fuel ratio sensor (sensor 1) connector.
• Disconnect the ECM connector.

• Measure the resistance according to the value(s) in the table below.

  Standard Resistance

  Tester Connection	Condition	Specified Condition
  C29-1 (HA1A) - C38-8 (HA1A)	Always	Below 1 Ω
  C29-3 (A1A+) - C38-56 (A1A+)	Always	Below 1 Ω
  C29-4 (A1A-) - C38-55 (A1A-)	Always	Below 1 Ω
  C30-1 (HA2A) - C38-7 (HA2A)	Always	Below 1 Ω
  C30-3 (A2A+) - C38-54 (A2A+)	Always	Below 1 Ω
  C30-4 (A2A-) - C38-53 (A2A-)	Always	Below 1 Ω
  C29-1 (HA1A) or C38-8 (HA1A) - Body ground and other terminals	Always	10 kΩ or higher
  C29-3 (A1A+) or C38-56 (A1A+) - Body ground and other terminals	Always	10 kΩ or higher
  C29-4 (A1A-) or C38-55 (A1A-) - Body ground and other terminals	Always	10 kΩ or higher
  C30-1 (HA2A) or C38-7 (HA2A) - Body ground and other terminals	Always	10 kΩ or higher
  C30-3 (A2A+) or C38-54 (A2A+) - Body ground and other terminals	Always	10 kΩ or higher
  C30-4 (A2A-) or C38-53 (A2A-) - Body ground and other terminals	Always	10 kΩ or higher

  Result

  Proceed to
  OK
  NG

Post-procedure1

• None

Result: 

NG 

REPAIR OR REPLACE HARNESS OR CONNECTOR 

Result: 

OK 

See step  33

HINT: 

Refer to REMOVAL [12/2021 - ]

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

Refer to INITIALIZATION [12/2021 - ]

Result

Result: 

NEXT 

See step  34

Pre-procedure1

• None

• Clear the DTCs.

  Powertrain > Engine > Clear DTCs 

  Result

  Proceed to
  NEXT

Post-procedure1

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

Result: 

NEXT 

See step  35

Pre-procedure1

• Drive the vehicle in accordance with the driving pattern described in Confirmation Driving Pattern.

• Read the DTCs.

  Powertrain > Engine > Trouble Codes 

  Result

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

Post-procedure1

• None

Result: 

A 

END 

Result: 

B 

See step  36

Pre-procedure1

• Start the engine.
• Allow the engine to idle until Coolant Temperature reaches 75°C (167°F) or higher.

• Read Mass Air Flow Sensor while maintaining an engine speed of 3000 rpm.

  Powertrain > Engine > Data List 

  Tester Display
  Engine Speed
  MAF Sensor Bank1
  MAF Sensor Bank2

  Standard

  GTS Display	Condition	Specified Condition
  MAF Sensor Bank1	Engine warmed up Shift position: N A/C: Off Engine Speed: 3000 rpm	Between 6.5 and 30.0 gm/sec
  MAF Sensor Bank2		Between 6.5 and 30.0 gm/sec

  Result

  Proceed to
  NEXT

Post-procedure1

• None

Result: 

NEXT 

See step  37

1. Check the connection and terminal contact pressure of connectors and wire harnesses between the mass air flow meter sub-assembly and ECM.

   HINT: 

   Refer to ELECTRONIC CIRCUIT INSPECTION PROCEDURE [12/2021 - ]

   Repair any problems.

   Result

   Proceed to
   NEXT

Result: 

NEXT 

See step  38

Pre-procedure1

• None

• Clear the DTCs.

  Powertrain > Engine > Clear DTCs 

  Result

  Proceed to
  NEXT

Post-procedure1

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

Result: 

NEXT 

See step  39

Pre-procedure1

• Drive the vehicle in accordance with the driving pattern described in Confirmation Driving Pattern.

• Read the DTCs.

  Powertrain > Engine > Trouble Codes 

  Result

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

Post-procedure1

• None

Result: 

A 

END 

Result: 

B 

See step  40

Pre-procedure1

• Disconnect the mass air flow meter sub-assembly connector.
• Disconnect the ECM connector.

• Measure the resistance according to the value(s) in the table below.

  Standard Resistance

  Tester Connection	Condition	Specified Condition
  C24-4 (VCCR) - C37-84 (VCVG)	Always	Below 1 Ω
  C24-3 (FGR) - C37-78 (VG)	Always	Below 1 Ω
  C24-2 (E2GR) - C37-83 (E2G)	Always	Below 1 Ω
  C25-4 (VCC) - C37-82 (VVG2)	Always	Below 1 Ω
  C25-3 (FG) - C37-76 (VG2)	Always	Below 1 Ω
  C25-2 (E2G) - C37-81 (E2G2)	Always	Below 1 Ω
  C24-4 (VCCR) or C37-84 (VCVG) - Body ground and other terminals	Always	10 kΩ or higher
  C24-3 (FGR) or C37-78 (VG) - Body ground and other terminals	Always	10 kΩ or higher
  C25-4 (VCC) or C37-82 (VVG2) - Body ground and other terminals	Always	10 kΩ or higher
  C25-3 (FG) or C37-76 (VG2) - Body ground and other terminals	Always	10 kΩ or higher

  Result

  Proceed to
  OK
  NG

Post-procedure1

• None

Result: 

NG 

REPAIR OR REPLACE HARNESS OR CONNECTOR 

Result: 

OK 

See step  41

Refer to ON-VEHICLE INSPECTION [12/2021 - ]

Result

Result: 

NEXT 

See step  42

Pre-procedure1

• None

• Clear the DTCs.

  Powertrain > Engine > Clear DTCs 

  Result

  Proceed to
  NEXT

Post-procedure1

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

Result: 

NEXT 

See step  43

Pre-procedure1

• Drive the vehicle in accordance with the driving pattern described in Confirmation Driving Pattern.

• Read the DTCs.

  Powertrain > Engine > Trouble Codes 

  Result

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

Post-procedure1

• None

Result: 

A 

END 

Result: 

B 

See step  44

HINT: 

Refer to REMOVAL [12/2021 - ]

Result

Result: 

NEXT 

See step  47

1. Repair or replace exhaust system.

   HINT: 

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

   Refer to INITIALIZATION [12/2021 - ]

   Result

   Proceed to
   NEXT

Result: 

NEXT 

See step  46

Pre-procedure1

• None

• Clear the DTCs.

  Powertrain > Engine > Clear DTCs 

  Result

  Proceed to
  NEXT

Post-procedure1

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

Result: 

NEXT 

See step  47

Pre-procedure1

• Drive the vehicle in accordance with the driving pattern described in Confirmation Driving Pattern.

• Read the DTCs.

  Powertrain > Engine > Trouble Codes 

  Result

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

Post-procedure1

• None

Result: 

A 

END 

Result: 

B 

See step  48

HINT: 

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

1. Read the DTCs.

   Powertrain > Engine > Trouble Codes 

   Result

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

Result: 

A 

REPLACE CONVERTER ASSEMBLY RH AND LH (TWC: FRONT AND REAR CATALYST). Refer to  REMOVAL [12/2021 - ] 

Result: 

B 

REPLACE CONVERTER ASSEMBLY RH (TWC: FRONT AND REAR CATALYST). Refer to  REMOVAL [12/2021 - ] 

Result: 

C 

REPLACE CONVERTER ASSEMBLY LH (TWC: FRONT AND REAR CATALYST). Refer to  REMOVAL [12/2021 - ] 

1. Check for exhaust gas leaks.

   OK

   No gas leaks in exhaust system.

   HINT: 

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

   Refer to INITIALIZATION [12/2021 - ]

   Result

   Proceed to
   OK
   NG

Result: 

NG 

REPAIR OR REPLACE EXHAUST SYSTEM 

Result: 

OK 

See step  50

HINT: 

Refer to REMOVAL [12/2021 - ]

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

Refer to INITIALIZATION [12/2021 - ]

Result

Result: 

NEXT 

See step  51

Pre-procedure1

• None

• Clear the DTCs.

  Powertrain > Engine > Clear DTCs 

  Result

  Proceed to
  NEXT

Post-procedure1

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

Result: 

NEXT 

See step  52

Pre-procedure1

• Drive the vehicle in accordance with the driving pattern described in Confirmation Driving Pattern.

• Read the DTCs.

  Powertrain > Engine > Trouble Codes 

  Result

  DTCs are not output.

  Result

  Proceed to
  NEXT

Post-procedure1

• None

Result: 

NEXT 

END