Nissan Altima L32. Manual - part 418

P0420 THREE WAY CATALYST FUNCTION

EC-793

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Diagnosis Procedure

INFOID:0000000004349759

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 (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 IGNITION TIMING

For procedure, refer to

EC-564, "IGNITION TIMING : Special Repair Requirement"

.

For specification, refer to

EC-1043, "Idle Speed"

 and

EC-1043, "Ignition Timing"

.

Is the inspection result normal?

YES

>> GO TO 5.

NO

>> Follow the 

EC-560, "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-956, "Diagnosis Procedure"

.

6.

CHECK FUNCTION OF IGNITION COIL-I

CAUTION:

PBIB1216E

ECM

Ground

Voltage

Connector

Terminal

F14

29

Ground

Battery voltage

30

31

32

JMBIA1593GB

EC-794

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P0420 THREE WAY CATALYST FUNCTION

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 pressure applies again during the following pro-

cedure.

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:

• 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.

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-963, "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-99, "Standard and Limit"

.

NO

>> Repair or clean spark plug. Then GO TO 9.

9.

CHECK FUNCTION OF IGNITION COIL-III

Spark should be generated.

JMBIA0066GB

Spark should be generated.

SEF156I

P0420 THREE WAY CATALYST FUNCTION

EC-795

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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-99, "Standard

and Limit"

.

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

>> GO TO 11.

NO

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

11.

CHECK INTERMITTENT INCIDENT

Refer to 

GI-42, "Intermittent Incident"

.

Is the inspection result normal?

YES

>> Replace three way catalyst assembly.

NO

>> Repair or replace harness or connector

Spark should be generated.

EC-796

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P0441 EVAP CONTROL SYSTEM

P0441 EVAP CONTROL SYSTEM

DTC Logic

INFOID:0000000004349760

DTC DETECTION LOGIC

NOTE:

If DTC P0441 is displayed with other DTC such as P2122, P2123, P2127, P2128 or P2138, first perform

trouble diagnosis for other DTC.

In this evaporative emission (EVAP) control system, purge flow occurs during non-closed throttle conditions.

Purge volume is related to air intake volume. Under normal purge conditions (non-closed throttle), the EVAP

canister purge volume control solenoid valve is open to admit purge flow. Purge flow exposes the EVAP con-

trol system pressure sensor to intake manifold vacuum.

Under normal conditions (non-closed throttle), sensor output voltage indicates if pressure drop and purge flow

are adequate. If not, a malfunction is determined.

DTC CONFIRMATION PROCEDURE

1.

INSPECTION START

Do you have CONSULT-III?
Do you have CONSULT-III?

YES

>> GO TO 2.

NO

>> GO TO 6.

2.

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:

DTC No.

Trouble diagnosis name

DTC detecting condition

Possible cause

P0441

EVAP control system in-
correct purge flow

EVAP control system does not operate proper-
ly, EVAP control system has a leak between in-
take manifold and EVAP control system 
pressure sensor.

• EVAP canister purge volume control so-

lenoid valve stuck closed

• EVAP control system pressure sensor 

and the circuit

• Loose, disconnected or improper con-

nection of rubber tube

• Blocked rubber tube
• Cracked EVAP canister
• EVAP canister purge volume control so-

lenoid valve circuit

• Accelerator pedal position sensor
• Blocked purge port
• EVAP canister vent control valve

PBIB1026E