Nissan Cube. Manual - part 341

EC-250

< DTC/CIRCUIT DIAGNOSIS >

[MR18DE]

P0420 THREE WAY CATALYST FUNCTION

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 2,000 to 3,000 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-250, "Diagnosis Procedure"

.

NO

>> INSPECTION END

7.

PERFORM COMPONENT FUNCTION CHECK

Perform component function check. Refer to 

EC-250, "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-250, "Diagnosis Procedure"

.

Component Function Check

INFOID:0000000009947367

1.

PERFORM COMPONENT FUNCTION CHECK

Without CONSULT

1.

Start engine and warm it up to 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.

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

Is the inspection result normal?

YES

>> INSPECTION END

NO

>> Go to 

EC-250, "Diagnosis Procedure"

.

Diagnosis Procedure

INFOID:0000000009947368

1.

CHECK EXHAUST SYSTEM

Visually check exhaust tubes and muffler for dent.

ECM

Ground

Condition

Voltage

Connector

Terminal

F8

50

(HO2S2 signal)

Ground

Keeping engine speed at 2,500 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

P0420 THREE WAY CATALYST FUNCTION

EC-251

< DTC/CIRCUIT DIAGNOSIS >

[MR18DE]

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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 (manifold).

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-18, "IGNITION TIMING : Special Repair Requirement"

.

For specification, refer to

EC-482, "Idle Speed"

 and 

EC-482, "Ignition Timing"

.

Is the inspection result normal?

YES

>> GO TO 5.

NO

>> Follow the instruction of 

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

.

5.

CHECK FUEL INJECTOR

1.

Stop engine and then turn ignition switch ON.

2.

Check the voltage between ECM harness connector and ground.

Is the inspection result normal?

YES

>> GO TO 6.

NO

>> Perform 

EC-406, "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 to release fuel pressure, or fuel pressure applies again during the following proce-
dure.

PBIB1216E

ECM

Ground

Voltage

Connector

Terminal

F7

25

Ground

Battery voltage

29

30

31

EC-252

< DTC/CIRCUIT DIAGNOSIS >

[MR18DE]

P0420 THREE WAY CATALYST FUNCTION

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 electrical 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:

• During the operation, always stay 0.5 m (19.7 in) away

from the spark plug and the ignition coil. Be careful not to
get an electrical shock while checking, because the elec-
trical discharge voltage becomes 20 kV 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.

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-412, "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-113, "Spark Plug"

.

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.

Spark should be generated.

JMBIA0066GB

Spark should be generated.

SEF156I

Spark should be generated.

P0420 THREE WAY CATALYST FUNCTION

EC-253

< DTC/CIRCUIT DIAGNOSIS >

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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-113, "Spark

Plug"

.

10.

CHECK FUEL INJECTOR

1.

Turn ignition switch OFF. Refer to 

EM-35, "Removal and Installation"

.

2.

Remove fuel injector assembly. Refer to 

EM-35, "Exploded View"

.

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

>> GO TO 11.

NO

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

EM-35, "Exploded View"

.

11.

CHECK INTERMITTENT INCIDENT

Refer to 

GI-40, "Intermittent Incident"

.

Is the inspection result normal?

YES

>> Replace three way catalyst assembly.

NO

>> Repair or replace harness or connector