Infiniti G37 Coupe. Manual - part 523

P0420, P0430 THREE WAY CATALYST FUNCTION

EC-273

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8.

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).

9.

Open engine hood.

10. Select “DTC & SRT CONFIRMATION” then “SRT WORK SUPPORT” mode with CONSULT-III.
11. Rev engine up to about 2,000 rpm and hold it for 3 consecutive minutes then release the accelerator

pedal completely.

12. Check the indication of “CATALYST”.

Which is displayed on CONSULT-III screen?

CMPLT >> GO TO 6.
INCMP >> GO TO 4.

4.

PERFORM DTC CONFIRMATION PROCEDURE-II

1.

Wait 5 seconds at idle.

2.

Rev engine up to about 2,000 rpm and maintain it until “INCMP” of “CATALYST” changes to “CMPLT” (It
will take approximately 5 minutes).

Does the indication change to “CMPLT”?

YES

>> GO TO 6.

NO

>> GO TO 5.

5.

PERFORM DTC CONFIRMATION PROCEDURE AGAIN

1.

Stop engine and cool it down to less than 70

°

C (158

°

F).

2.

Perform DTC CONFIRMATION PROCEDURE again.

>> GO TO 3.

6.

PERFORM DTC CONFIRMATION PROCEDURE-III

Check 1st trip DTC.

Is 1st trip DTC detected?

YES

>> Go to 

EC-274, "Diagnosis Procedure"

.

NO

>> INSPECTION END

7.

PERFORM COMPONENT FUNCTION CHECK

Perform component function check. Refer to 

EC-273, "Component Function Check"

.

NOTE:
Use component function check to check the overall function of the three way catalyst (manifold). During this
check, a 1st trip DTC might not be confirmed.
Is the inspection result normal?

YES

>> INSPECTION END

NO

>> Go to 

EC-274, "Diagnosis Procedure"

.

Component Function Check

INFOID:0000000001734100

1.

PERFORM COMPONENT FUNCTION CHECK

Without CONSULT-III

1.

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

2.

Turn ignition switch OFF and wait at least 10 seconds.

3.

Turn ignition switch ON.

4.

Turn ignition switch OFF and wait at least 10 seconds.

5.

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

6.

Let engine idle for 1 minute.

7.

Open engine hood.

8.

Check the voltage between ECM harness connector and ground under the following condition.

EC-274

< COMPONENT DIAGNOSIS >

[VQ37VHR]

P0420, P0430 THREE WAY CATALYST FUNCTION

Is the inspection result normal?

YES

>> INSPECTION END

NO

>> Go to 

EC-274, "Diagnosis Procedure"

.

Diagnosis Procedure

INFOID:0000000001734101

1.

CHECK EXHAUST SYSTEM

Visually check exhaust tubes and muffler for dent.
Is the inspection result normal?

YES

>> GO TO 2.

NO

>> 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 1.

Is exhaust gas leak detected?

YES

>> Repair or replace.

NO

>> GO TO 3.

3.

CHECK INTAKE AIR LEAK

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

Is intake air leak detected?

YES

>> Repair or replace.

NO

>> GO TO 4.

4.

CHECK IDLE SPEED AND IGNITION TIMING

For procedure, refer to 

EC-13, "BASIC INSPECTION : Special Repair Requirement"

.

For specification, refer to 

EC-606, "Idle Speed"

 and 

EC-606, "Ignition Timing"

.

Is the inspection result normal?

YES

>> GO TO 5.

NO

>> Follow the 

EC-13, "BASIC INSPECTION : Special Repair Requirement"

.

5.

CHECK FUEL INJECTORS

1.

Stop engine and then turn ignition switch ON.

2.

Check the voltage between ECM harness connector and ground.

DTC

ECM

Ground

Condition

Voltage

Connector

Terminal

P0420

F102

76

[HO2S2 (bank 1)]

Ground

Keeping engine speed at 2500 rpm 
constant under no load

The voltage fluctuation cycle takes more 
than 5 seconds.
• 1 cycle: 0.6 - 1.0 

→

 0 - 0.3 

→

 0.6 - 1.0

P0430

80

[HO2S2 (bank 2)]

PBIB1922E

P0420, P0430 THREE WAY CATALYST FUNCTION

EC-275

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Is the inspection result normal?

YES

>> GO TO 6.

NO

>> Perform 

EC-487, "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 (1) in IPDM E/R (2) to release fuel pres-
sure.
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 5 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 (0.52 -

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

11. Crank engine for about 3 seconds, and check whether spark is

generated between the spark plug and the grounded metal por-
tion.

CAUTION:

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

within 50 cm (19.7 in). 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 (0.66 in) is taken.
NOTE:
When the gap is less than 13 mm (0.52 in), the spark might be generated even if the coil is mal-
functioning.

Is the inspection result normal?

YES

>> GO TO 10.

NO

>> 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.

ECM

Ground

Voltage

Connector

Terminal

F102

81

Ground

Battery voltage

82

85

86

89

90

Spark should be generated.

JMBIA0021ZZ

JMBIA0066GB

EC-276

< COMPONENT DIAGNOSIS >

[VQ37VHR]

P0420, P0430 THREE WAY CATALYST FUNCTION

3.

Crank engine for about 3 seconds, and recheck whether spark is generated between the spark plug and
the grounded metal portion.

Is the inspection result normal?

YES

>> GO TO 8.

NO

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

EC-498, "Diagnosis Procedure"

.

8.

CHECK SPARK PLUG

Check the initial spark plug for fouling, etc.

Is the inspection result normal?

YES

>> Replace spark plug(s) with standard type one(s). For

spark plug type, refer to 

EM-16, "Inspection"

.

NO

>> Repair or clean spark plug. Then 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.

Is the inspection result normal?

YES

>> INSPECTION END

NO

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

EM-15, "Removal

and Installation"

.

10.

CHECK FUEL INJECTOR

1.

Turn ignition switch OFF.

2.

Remove fuel injector assembly.
Refer to 

EM-36, "Removal and Installation"

.

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

3.

Disconnect all ignition coil harness connectors.

4.

Reconnect all fuel injector harness connectors disconnected.

5.

Turn ignition switch ON.

Does fuel drip from fuel injector?

YES

>> Replace the fuel injector(s) from which fuel is dripping.

NO

>> GO TO 11.

11.

CHECK INTERMITTENT INCIDENT

Refer to 

GI-38, "Intermittent Incident"

.

Is the trouble fixed?

YES

>> INSPECTION END

NO

>> Replace three way catalyst assembly.

Spark should be generated.

SEF156I

Spark should be generated.