СИСТЕМА SFI, Diagnostic DTC:P0420, P0430

Информация добавлена 08-08-2017

DTC Code	DTC Name
P0420	Catalyst System Efficiency Below Threshold (Bank 1)
P0430	Catalyst System Efficiency Below Threshold (Bank 2)

MONITOR DESCRIPTION

The ECM uses sensors mounted in front of and behind the Three-Way Catalytic Converter (TWC) to monitor its efficiency.

The first sensor, the air fuel ratio sensor, sends pre-catalyst information to the ECM. The second sensor, the heated oxygen sensor, sends post-catalyst information to the ECM.

In order to detect any deterioration in the three-way catalytic converter, the ECM calculates the oxygen storage capacity of the three-way catalytic converter. This calculation is based on the voltage output of the heated oxygen sensor while performing active air fuel ratio control.

The oxygen storage capacity value is an indication of the oxygen storage capacity of the three-way catalytic converter. When the vehicle is being driven with a warm engine, active air fuel ratio control is performed for approximately 15 to 20 seconds. When it is performed, the ECM deliberately sets the air fuel ratio to lean or rich levels. If the cycle of the waveform for the heated oxygen sensor is long, the oxygen storage capacity is great. There is a direct correlation between the heated oxygen sensor and the oxygen storage capacity of the three-way catalytic converter.

The ECM uses the oxygen storage capacity value to determine the state of the three-way catalytic converter. If any deterioration has occurred, the ECM illuminates the MIL and stores the DTC.

This system determines the deterioration of the entire catalyst system (including the front and rear catalysts), by using the oxygen storage capacity value of the front catalyst, which is more sensitive than the rear catalyst, as the representative value. Therefore, be sure to replace the front and rear catalysts together when catalyst replacement is necessary.

DTC No.	Detection Item	DTC Detection Condition	Trouble Area	MIL	Memory
P0420	Catalyst System Efficiency Below Threshold (Bank 1)	The oxygen storage capacity value is less than the standard value under active air fuel ratio control (2 trip detection logic).	Gas leak from exhaust system Air fuel ratio sensor (bank 1 sensor 1) Heated oxygen sensor (bank 1 sensor 2) Exhaust manifold sub-assembly RH (TWC: Front catalyst) and front exhaust pipe assembly (TWC: Rear catalyst)	Comes on	DTC stored
P0430	Catalyst System Efficiency Below Threshold (Bank 2)	The oxygen storage capacity value is less than the standard value under active air fuel ratio control (2 trip detection logic).	Gas leak from exhaust system Air fuel ratio sensor (bank 2 sensor 1) Heated oxygen sensor (bank 2 sensor 2) Exhaust manifold sub-assembly LH (TWC: Front catalyst) and front No. 2 exhaust pipe assembly (TWC: Rear catalyst)	Comes on	DTC stored

CATALYST LOCATION

*1	Exhaust Manifold Sub-assembly RH (TWC: Front catalyst)	*2	Exhaust Manifold Sub-assembly LH (TWC: Front catalyst)
*3	Front Exhaust Pipe (TWC: Rear catalyst)	*4	Front No. 2 Exhaust Pipe (TWC: Rear catalyst)
*5	Center Exhaust Pipe Assembly	*6	Tailpipe Assembly
*7	Air Fuel Ratio Sensor (for Bank 1 Sensor 1)	*8	Air Fuel Ratio Sensor (for Bank 2 Sensor 1)
*9	Heated Oxygen Sensor (for Bank 1 Sensor 2)	*10	Heated Oxygen Sensor (for Bank 2 Sensor 2)

Note

When DTC P0420 is output, replace the exhaust manifold sub-assembly RH (^*1) and the front exhaust pipe assembly (^*3) together when catalyst replacement is necessary (excluding air fuel ratio sensor^*7 and heated oxygen sensor^*9).
When DTC P0430 is output, replace the exhaust manifold sub-assembly LH (^*2) and the front No. 2 exhaust pipe assembly (^*4) together when catalyst replacement is necessary (excluding air fuel ratio sensor^*8 and heated oxygen sensor^*10).

CONFIRMATION DRIVING PATTERN

Tech Tips

Performing this confirmation driving pattern will activate the catalyst efficiency monitor. This is very useful for verifying the completion of a repair.

Connect the GTS to the DLC3.
Turn the engine switch on (IG).
Turn the GTS on.
Clear DTCs (even if no DTCs are stored, perform the clear DTC operation).
Turn the engine switch off and wait for at least 30 seconds.
Turn the engine switch on (IG) and turn the GTS on.
Start the engine and warm it up until the engine coolant temperature is 75°C (167°F) or higher [A].
Drive the vehicle at approximately 60 km/h (37 mph) for 10 minutes or more [B].

CAUTION:

When performing the confirmation driving pattern, obey all speed limits and traffic laws.

Tech Tips

Drive the vehicle while keeping the engine load as constant as possible.
Turn the engine switch off and wait for at least 30 seconds [C].
Turn the engine switch on (IG) and turn the GTS on.
Start the engine and warm it up until the engine coolant temperature is 75°C (167°F) or higher [D].
Drive the vehicle at approximately 60 km/h (37 mph) for 10 minutes or more [E].

CAUTION:

When performing the confirmation driving pattern, obey all speed limits and traffic laws.

Tech Tips

Drive the vehicle while keeping the engine load as constant as possible.
Enter the following menus: Powertrain / Engine and ECT / Trouble Codes [F].
Check if any DTCs (pending DTCs) are stored.
Tech Tips
- If a pending DTC is output, the system is malfunctioning.
- If a pending DTC is not output, perform the following procedure.
Drive the vehicle at a speed between 75 and 100 km/h (47 and 63 mph) for 10 minutes or more [G].

CAUTION:

When performing the confirmation driving pattern, obey all speed limits and traffic laws.

Tech Tips

Drive the vehicle while keeping the engine load as constant as possible.
Enter the following menus: Powertrain / Engine and ECT / Utility / All Readiness [H].
Input the DTC: P0420.

Check the DTC judgment result.

GTS Display	Description
NORMAL	DTC judgment completed System normal
ABNORMAL	DTC judgment completed System abnormal
INCOMPLETE	DTC judgment not completed Perform driving pattern after confirming DTC enabling conditions
N/A	Unable to perform DTC judgment Number of DTCs which do not fulfill DTC preconditions has reached ECU memory limit

Tech Tips

If the judgment result shows NORMAL, the system is normal.
If the judgment result shows ABNORMAL, the system has a malfunction.

CONDITIONING FOR SENSOR TESTING

Tech Tips

Perform the operation with the engine speeds and time durations described below prior to checking the waveforms of the air fuel ratio and heated oxygen sensors. This is to activate the sensors sufficiently to obtain appropriate inspection results.

(a) Connect the GTS to the DLC3.

(b) Start the engine and warm it up with all the accessories switched off until the engine coolant temperature stabilizes.

(d) While running the engine at 3000 rpm for 2 seconds, and then 2000 rpm for 2 seconds, check the waveforms of the air fuel ratio and heated oxygen sensors using the GTS.

Tech Tips

If the voltage output of either the air fuel ratio or heated oxygen sensor does not fluctuate, or there is a noise in the waveform of either sensor, the sensor may be malfunctioning.
If the voltage outputs of both the sensors remain lean or rich, the air fuel ratio may be extremely lean or rich. In such cases, perform the Control the Injection Volume for A/F Sensor Active Test using the GTS.
If the Three-way Catalytic Converter (TWC) has deteriorated, the heated oxygen sensor (located behind the Three-way Catalytic Converter [TWC]) voltage output fluctuates up and down frequently, even under normal driving conditions (active air fuel ratio control is not performed).

CAUTION / NOTICE / HINT

Tech Tips

Bank 1 refers to the bank that includes the No. 1 cylinder^*.

^*: The No. 1 cylinder is the cylinder which is farthest from the transmission.
Bank 2 refers to the bank that does not include the No. 1 cylinder.
Sensor 1 refers to the sensor closest to the engine assembly.
Sensor 2 refers to the sensor farthest away from the engine assembly.
If a malfunction cannot be found when troubleshooting DTC P0420 or P0430, a lean or rich abnormality may be the cause. Perform troubleshooting by following the inspection procedure for P0171, P0174 (System Too Lean) and P0172, P0175 (System Too Rich).
Read freeze frame data using the GTS. The ECM records vehicle and driving condition information as freeze frame data the moment a DTC is stored. When troubleshooting, freeze frame data can help determine if the vehicle was moving or stationary, if the engine was warmed up or not, if the air fuel ratio was lean or rich, and other data from the time the malfunction occurred.

PROCEDURE

CHECK FOR ANY OTHER DTCS OUTPUT (IN ADDITION TO DTC P0420 AND/OR P0430)

Connect the GTS to the DLC3.
Turn the engine switch on (IG).
Turn the GTS on.
Enter the following menus: Powertrain / Engine and ECT / Trouble Codes.

Powertrain > Engine and ECT > Trouble Codes

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

Tech Tips

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

GO TO DTC CHART Click here

PERFORM ACTIVE TEST USING GTS (CONTROL THE INJECTION VOLUME FOR A/F SENSOR)

Connect the GTS to the DLC3.
Start the engine and warm it up.
Turn the GTS on.
Run the engine at an engine speed of 2500 rpm for approximately 90 seconds.
Enter the following menus: Powertrain / Engine and ECT / Active Test / Control the Injection Volume for A/F Sensor / Ptrl AF Control / AFS Voltage B1S1 and O2S B1S2 or AFS Voltage B2S1 and O2S B2S2.

Powertrain > Engine and ECT > Active Test

Tester Display

Control the Injection Volume for A/F Sensor
Perform the Active Test operation with the engine idling (press the RIGHT or LEFT button to change the fuel injection volume).

Tester Display
Control the Injection Volume for A/F Sensor

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 GTS.

Tech Tips

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

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

Result

StatusAFS Voltage B1S1 or AFS Voltage B2S1	StatusO2S B1S2 or O2S B2S2	Actual air fuel ratio, air fuel ratio sensor andheated oxygen sensor condition	Misfire	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	B
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	C
Lean	Lean	Actual air fuel ratio lean	May occur	Extremely rich or lean actual air fuel ratio Gas leak from exhaust system	D
Rich	Rich	Actual air fuel ratio lean	-	Extremely rich or lean actual air fuel ratio Gas leak from exhaust system	D

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.

REPLACE AIR FUEL RATIO SENSOR Click here

CHECK FOR EXHAUST GAS LEAK Click here

CHECK FOR EXHAUST GAS LEAK

Check for exhaust gas leaks.

OK
No gas leaks.

Result

Proceed to
OK
NG

GO TO STEP 12 Click here

CHECK DTC OUTPUT (DTC P0420 AND/OR P0430)

Note

When DTC P0420 is output, replace the exhaust manifold sub-assembly RH (TWC: Front catalyst) and the front exhaust pipe assembly (TWC: Rear catalyst) together when catalyst replacement is necessary.
When DTC P0430 is output, replace the exhaust manifold sub-assembly LH (TWC: Front catalyst) and the front No. 2 exhaust pipe assembly (TWC: Rear catalyst) together when catalyst replacement is necessary.

Tech Tips

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

Connect the GTS to the DLC3.
Turn the engine switch on (IG).
Turn the GTS on.
Enter the following menus: Powertrain / Engine and ECT / Trouble Codes.

Powertrain > Engine and ECT > Trouble Codes

Read the DTCs.

Result

Proceed to

DTC P0420 is output

DTC P0430 is output

DTC P0420 and P0430 are output

A, B, C, D

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

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

REPLACE FRONT EXHAUST PIPE ASSEMBLY (TWC: REAR CATALYST) Click here

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

REPLACE AIR FUEL RATIO SENSOR

Replace the air fuel ratio sensor.

Click here

Result

Proceed to
NEXT

GO TO STEP 10 Click here

CHECK FOR EXHAUST GAS LEAK

Check for exhaust gas leaks.

OK
No gas leaks.

Result

Proceed to
OK
NG

REPLACE HEATED OXYGEN SENSOR

Replace the heated oxygen sensor.

Click here

Result

Proceed to
NEXT

GO TO STEP 10 Click here

CHECK FOR EXHAUST GAS LEAK

Check for exhaust gas leaks.

OK
No gas leaks.

Result

Proceed to
OK
NG

REPAIR OR REPLACE EXHAUST GAS LEAK POINT Click here

CHECK CAUSE OF EXTREMELY RICH OR LEAN ACTUAL AIR FUEL RATIO

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

Click here

Result

Proceed to
NEXT

CONFIRM WHETHER MALFUNCTION HAS BEEN SUCCESSFULLY REPAIRED

Connect the GTS to the DLC3.
Turn the engine switch on (IG).
Turn the GTS on.
Clear the DTCs.

Click here

Powertrain > Engine and ECT > Clear DTCs
Turn the engine switch off and wait for at least 30 seconds.
Start the engine.
Turn the GTS on.
Drive the vehicle in accordance with the driving pattern described in the Confirmation Driving Pattern.
Enter the following menus: Powertrain / Engine and ECT / Trouble Codes.

Powertrain > Engine and ECT > Trouble Codes

Read the DTCs.

Result

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

END

CHECK DTC OUTPUT (DTC P0420 AND/OR P0430)

Note

When DTC P0420 is output, replace the exhaust manifold sub-assembly RH (TWC: Front catalyst) and the front exhaust pipe assembly (TWC: Rear catalyst) together when catalyst replacement is necessary.
When DTC P0430 is output, replace the exhaust manifold sub-assembly LH (TWC: Front catalyst) and the front No. 2 exhaust pipe assembly (TWC: Rear catalyst) together when catalyst replacement is necessary.

Tech Tips

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

Connect the GTS to the DLC3.
Turn the engine switch on (IG).
Turn the GTS on.
Enter the following menus: Powertrain / Engine and ECT / Trouble Codes.

Powertrain > Engine and ECT > Trouble Codes

Read the DTCs.

Result

Proceed to

DTC P0420 is output

DTC P0430 is output

DTC P0420 and P0430 are output

A, B, C, D

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

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

REPLACE FRONT EXHAUST PIPE ASSEMBLY (TWC: REAR CATALYST) Click here

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

REPAIR OR REPLACE EXHAUST GAS LEAK POINT

Repair or replace exhaust gas leak point.

Result

Proceed to
NEXT

GO TO STEP 10 Click here