Infiniti FX35 / FX45. Manual - part 539

DTC P0420, P0430 THREE WAY CATALYST FUNCTION

EC-917

< SERVICE INFORMATION >

[VK45DE]

C

D

E

F

G

H

I

J

K

L

M

A

EC

N

P

O

DTC P0420, P0430 THREE WAY CATALYST FUNCTION

On Board Diagnosis Logic

INFOID:0000000001326754

The ECM monitors the switching frequency ratio of air fuel ratio (A/F)
sensor 1 and heated oxygen sensor 2.
A three way catalyst (manifold) with high oxygen storage capacity
will indicate a low switching frequency of heated oxygen sensor 2.
As oxygen storage capacity decreases, the heated oxygen sensor 2
switching frequency will increase.
When the frequency ratio of A/F sensor 1 and heated oxygen sensor
2 approaches a specified limit value, the three way catalyst (mani-
fold) malfunction is diagnosed.

DTC Confirmation Procedure

INFOID:0000000001326755

NOTE:
If DTC Confirmation Procedure has been previously conducted, always turn ignition switch OFF and wait at
least 10 seconds before conducting the next test.

 WITH CONSULT-III

TESTING CONDITION:
Do not hold engine speed for more than the specified minutes below.
1.

Turn ignition switch ON and select “COOLAN TEMP/S” in “DATA MONITOR” mode with CONSULT-III.

2.

Start engine and warm it up to the normal operating temperature.

3.

Turn ignition switch OFF and wait at least 10 seconds.

4.

Start engine and keep the engine speed between 3,500 and 4,000 rpm for at least 1 minute under no load.

5.

Let engine idle for 1 minute.

6.

Make sure that “COOLAN TEMP/S” indicates more than 70

°

C (158

°

F).

If not, warm up engine and go to next step when “COOLAN TEMP/S” indication reaches to 70

°

C (158

°

F).

7.

Open engine hood.

8.

Select “DTC & SRT CONFIRMATION” then “SRT WORK SUPPORT” mode with CONSULT-III.

9.

Rev engine up to 2,000 to 3,000 rpm and hold it for 3 consecutive minutes then release the accelerator
pedal completely.
If “INCMP” of “CATALYST” changed to “CMPLT”, go to step 12.

10. Wait 5 seconds at idle.

11. Rev engine up to 2,000 to 3,000 rpm and maintain it until “INCMP” of “CATALYST” changes to “CMPLT” (It

will take approximately 5 minutes).
If not “CMPLT”, stop engine and cool it down to less than 70

°

C (158

°

F) and then retest from step 1.

12. Check 1st trip DTC.

13. If the 1st trip DTC is detected, go to 

EC-918, "Diagnosis Procedure"

.

PBIB2055E

DTC No.

Trouble diagnosis name

DTC detecting condition

Possible cause

P0420
0420
(Bank 1)

Catalyst system efficien-
cy below threshold

• Three way catalyst (manifold) does not oper-

ate properly.

• Three way catalyst (manifold) does not have 

enough oxygen storage capacity.

• Three way catalyst (manifold)
• Exhaust tube
• Intake air leaks
• Fuel injector
• Fuel injector leaks
• Spark plug
• Improper ignition timing

P0430
0430
(Bank 2)

EC-918

< SERVICE INFORMATION >

[VK45DE]

DTC P0420, P0430 THREE WAY CATALYST FUNCTION

Overall Function Check

INFOID:0000000001326756

Use this procedure to check the overall function of the three way catalyst (manifold). During this check, a 1st
trip DTC might not be confirmed.

 WITH GST

1.

Start engine and warm it up to the normal operating temperature.

2.

Turn ignition switch OFF and wait at least 10 seconds.

3.

Start engine and keep the engine speed between 3,500 and 4,000 rpm for at least 1 minute under no load.

4.

Let engine idle for 1 minute.

5.

Open engine hood.

6.

Set voltmeter probe between ECM terminals ECM terminals 55
[HO2S2 (Bank 1) signal], 74 [HO2S2 (Bank 2) signal] and
ground.

7.

Keep engine speed at 2,500 rpm constant under no load.

8.

Make sure that the voltage does not vary for more than 5 sec-
onds.
If the voltage fluctuation cycle takes less than 5 seconds, go to

EC-918, "Diagnosis Procedure"

.

• 1 cycle: 0.6 - 1.0 

→

 0 - 0.3 

→

 0.6 - 1.0

Diagnosis Procedure

INFOID:0000000001326757

1.

CHECK EXHAUST SYSTEM

Visually check exhaust tubes and muffler for dent.

OK or NG

OK

>> GO TO 2.

NG

>> Repair or replace.

2.

CHECK EXHAUST GAS LEAK

1.

Start engine and run it at idle.

2.

Listen for an exhaust gas leak before the three way catalyst (Manifold).

OK or NG

OK

>> GO TO 3.

NG

>> Repair or replace.

3.

CHECK INTAKE AIR LEAK

Listen for an intake air leak after the mass air flow sensor.
OK or NG

OK

>> GO TO 4.

NG

>> Repair or replace.

4.

CHECK IGNITION TIMING

Check the following items. Refer to 

EC-658, "Basic Inspection"

.

PBIB2056E

PBIB1216E

DTC P0420, P0430 THREE WAY CATALYST FUNCTION

EC-919

< SERVICE INFORMATION >

[VK45DE]

C

D

E

F

G

H

I

J

K

L

M

A

EC

N

P

O

OK or NG

OK

>> GO TO 5.

NG

>> Follow the 

EC-658, "Basic Inspection"

.

5.

CHECK FUEL INJECTORS

1.

Stop engine and then turn ignition switch ON.

2.

Check voltage between ECM terminals 21, 22, 23, 40, 41, 42,
44, 63 and ground with CONSULT-III or tester.
Refer to Wiring Diagram for fuel injectors, 

EC-1150

.

OK or NG

OK

>> GO TO 6.

NG

>> Perform 

EC-1151, "Diagnosis Procedure"

.

6.

CHECK FUNCTION OF IGNITION COIL-I

CAUTION:

Do the following procedure in the place where ventilation is good without the combustible.
1.

Turn ignition switch OFF.

2.

Remove fuel pump fuse in IPDM E/R to release fuel pressure.
NOTE:
Do not use CONSULT-III to release fuel pressure, or fuel pres-
sure applies again during the following procedure.

3.

Start engine.

4.

After engine stalls, crank it two or three times to release all fuel
pressure.

5.

Turn ignition switch OFF.

6.

Remove all ignition coil harness connectors to avoid the electri-
cal discharge from the ignition coils.

7.

Remove ignition coil and spark plug of the cylinder to be
checked.

8.

Crank engine for five seconds or more to remove combustion gas in the cylinder.

9.

Connect spark plug and harness connector to ignition coil.

10. Fix ignition coil using a rope etc. with gap of 13 - 17 mm

between the edge of the spark plug and grounded metal portion
as shown in the figure.

11. Crank engine for about three seconds, and check whether spark

is generated between the spark plug and the grounded metal
portion.

CAUTION:

• Do not approach to the spark plug and the ignition coil

within 50cm. Be careful not to get an electrical shock
while checking, because the electrical discharge voltage
becomes 20kV or more.

• It might cause to damage the ignition coil if the gap of more than 17 mm is taken.
NOTE:
When the gap is less than 13 mm, the spark might be generated even if the coil is malfunctioning.

OK or NG

OK

>> GO TO 10.

Items

Specifications

Ignition timing

12

°

 

±

 5

°

 BTDC (in P or N position)

Target idle speed

650 

±

 50 rpm (in P or N position)

Voltage: Battery voltage

PBIB1527E

Spark should be generated.

PBIB1482E

PBIB2325E

EC-920

< SERVICE INFORMATION >

[VK45DE]

DTC P0420, P0430 THREE WAY CATALYST FUNCTION

NG

>> GO TO 7.

7.

CHECK FUNCTION OF IGNITION COIL-II

1.

Turn ignition switch OFF.

2.

Disconnect spark plug and connect a known-good spark plug.

3.

Crank engine for about three seconds, and recheck whether spark is generated between the spark plug
and the grounded metal portion.

OK or NG

OK

>> GO TO 8.

NG

>> Check ignition coil, power transistor and their circuits. Refer to 

EC-1166

.

8.

CHECK SPARK PLUG

Check the initial spark plug for fouling, etc.
OK or NG

OK

>> Replace malfunctioning spark plug(s) with standard type

one(s). For spark plug type, refer to 

EM-188

.

NG

>> 1.

Repair or clean spark plug.

2.

GO TO 9.

9.

CHECK FUNCTION OF IGNITION COIL-III

1.

Reconnect the initial spark plugs.

2.

Crank engine for about three seconds, and recheck whether spark is generated between the spark plug
and the grounded portion.

OK or NG

OK

>> INSPECTION END

NG

>> Replace malfunctioning spark plug(s) with standard type one(s). For spark plug type, refer to 

EM-

188

.

10.

CHECK FUEL INJECTOR

1.

Turn ignition switch OFF.

2.

Remove fuel tube assembly.
Refer to 

EM-190

.

Keep fuel hose and all fuel injectors connected to fuel tube.

3.

Reconnect all fuel injector harness connectors disconnected.

4.

Disconnect all ignition coil harness connectors.

5.

Turn ignition switch ON.
Make sure fuel does not drip from fuel injector.

OK or NG

OK (Does not drip.)>>GO TO 11.
NG (Drips.)>>Replace the fuel injector(s) from which fuel is dripping.

11.

CHECK INTERMITTENT INCIDENT

Refer to 

EC-717

.

Trouble is fixed.>>INSPECTION END
Trouble is not fixed.>>Replace malfunctioning three way catalyst assembly.

Spark should be generated.

SEF156I

Spark should be generated.