Content .. 186 187 188 189 ..

Nissan March K13. Manual - part 188

P0420 THREE WAY CATALYST FUNCTION

EC-213

< DTC/CIRCUIT DIAGNOSIS >

[HR12DE (TYPE 1)]

P0420 THREE WAY CATALYST FUNCTION

DTC Logic

INFOID:0000000005989298

DTC DETECTION LOGIC

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 air fuel ratio (A/F) sensor 1 and heated
oxygen sensor 2 approaches a specified limit value, the three way
catalyst (manifold) malfunction is diagnosed.

DTC CONFIRMATION PROCEDURE

INSPECTION START

Do you have CONSULT-III?

YES

>> GO TO 2.

>> GO TO 7.

PRECONDITIONING

If DTC Confirmation Procedure has been previously conducted, always turn ignition switch OFF and wait at
least 10 seconds before conducting the next test.
TESTING CONDITION:
Do not hold engine speed for more than the specified minutes below.

>> GO TO 3.

PERFORM DTC CONFIRMATION PROCEDURE-I

With CONSULT-III

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

Turn ignition switch OFF and wait at least 10 seconds.

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

Let engine idle for 1 minute.

Select “COOLAN TEMP/S” in “DATA MONITOR” mode with CONSULT-III.

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).

Open engine hood.

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

Rev engine up to 2,000 to 3,000 rpm and hold it for 3 consecutive minutes then release the accelerator
pedal completely.

10. Check the indication of “CATALYST”.

Which is displayed on CONSULT-III screen?

SEF484YB

DTC No.

Trouble diagnosis name

DTC detecting condition

Possible cause

P0420

Catalyst system efficiency
below threshold

• Three way catalyst (manifold) does not operate

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

EC-214

< DTC/CIRCUIT DIAGNOSIS >

[HR12DE (TYPE 1)]

P0420 THREE WAY CATALYST FUNCTION

CMPLT >> GO TO 6.
INCMP >> GO TO 4.

PERFORM DTC CONFIRMATION PROCEDURE-II

Wait 5 seconds at idle.

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.

>> GO TO 5.

PERFORM DTC CONFIRMATION PROCEDURE AGAIN

Stop engine and cool it down to less than 70

C (158

F).

Perform DTC CONFIRMATION PROCEDURE again.

>> GO TO 3.

PERFORM DTC CONFIRMATION PROCEDURE-III

Check 1st trip DTC.

Is 1st trip DTC detected?

YES

>> Go to

EC-215, "Diagnosis Procedure"

>> INSPECTION END

PERFORM COMPONENT FUNCTION CHECK

Perform component function check. Refer to

EC-214, "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

>> Go to

EC-215, "Diagnosis Procedure"

Component Function Check

INFOID:0000000005989299

PERFORM COMPONENT FUNCTION CHECK

Without CONSULT-III

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

Turn ignition switch OFF and wait at least 10 seconds.

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

Let engine idle for 1 minute.

Open engine hood.

Check the voltage between ECM harness connector terminals under the following condition.

Is the inspection result normal?

YES

>> INSPECTION END

>> Go to

EC-215, "Diagnosis Procedure"

ECM

Condition

Voltage (V)

Connector

–

Terminal

F16

(HO2S2)

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

P0420 THREE WAY CATALYST FUNCTION

EC-215

< DTC/CIRCUIT DIAGNOSIS >

[HR12DE (TYPE 1)]

Diagnosis Procedure

INFOID:0000000005989300

CHECK EXHAUST SYSTEM

Visually check exhaust tubes and muffler for dent.

Is the inspection result normal?

YES

>> GO TO 2.

>> Repair or replace.

CHECK EXHAUST GAS LEAK

Start engine and run it at idle.

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

Is exhaust gas leak detected?

YES

>> Repair or replace.

>> GO TO 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.

>> GO TO 4.

CHECK IGNITION TIMING AND IDLE SPEED

Check the following items. Refer to

EC-109, "Work Procedure"

For specification, refer to

EC-315, "Ignition Timing"

For specification, refer to

EC-315, "Idle Speed"

Is the inspection result normal?

YES

>> GO TO 5.

>> Follow the

EC-109, "Work Procedure"

CHECK FUEL INJECTOR

Stop engine and then turn ignition switch ON.

Check the voltage between ECM harness connector and ground.

Is the inspection result normal?

YES

>> GO TO 6.

>> Perform

EC-285, "Diagnosis Procedure"

CHECK FUNCTION OF IGNITION COIL-I

CAUTION:

PBIB1216E

ECM

Voltage

Connector

Terminal

−

107

Battery voltage

EC-216

< DTC/CIRCUIT DIAGNOSIS >

[HR12DE (TYPE 1)]

P0420 THREE WAY CATALYST FUNCTION

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

Turn ignition switch OFF.

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

Start engine.

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

Turn ignition switch OFF.

Remove all ignition coil harness connectors to avoid the electrical discharge from the ignition coils.

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

Crank engine for 5 seconds or more to remove combustion gas in the cylinder.

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 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.

>> GO TO 7.

CHECK FUNCTION OF IGNITION COIL-II

Turn ignition switch OFF.

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

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.

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