Nissan Altima L32. Manual - part 291

P0340 CMP SENSOR (PHASE)

EC-285

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Check resistance camshaft position sensor (PHASE) terminals as

follows.

Is the inspection result normal?

YES

>> INSPECTION END

NO

>> Replace camshaft position sensor (PHASE).

Terminals (Polarity)

Resistance

1 (+) - 2 (-)

Except 0 or 

∞Ω [at 25°C (77°F)]

1 (+) - 3 (-)

2 (+) - 3 (-)

PBIA9584J

EC-286

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P0420 THREE WAY CATALYST FUNCTION

P0420 THREE WAY CATALYST FUNCTION

DTC Logic

INFOID:0000000004349324

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 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

1.

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 2.

2.

PERFORM DTC CONFIRMATION PROCEDURE-I

CAUTION:

Always drive vehicle in safe manner according to traffic conditions and obey all traffic laws.

With CONSULT-III

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

2. Repeat the following procedure 3 times.

-

Drive vehicle at a speed of 80 km/h (50 MPH) or more for at least 3 consecutive minutes.

NOTE:

Keep the vehicle speed as steady as possible during the cruising.

-

Stop vehicle with engine running.

NOTE:

Never turn ignition switch OFF.

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

4. Drive vehicle at a speed of 80 km/h (50MPH) or more until “INCMP” of “CATALYST”changes to“CMPLT”.

NOTE:

• Keep the vehicle speed as steady as possible during the cruising.

• It will take at most 3 minutes until “INCMP” of “CATALYST” changes to “CMPLT”.

5. Check 1st trip DTC.

With GST

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

2. Repeat the following procedure 3 times.

-

Drive vehicle at a speed of 80 km/h (50 MPH) or more for at least 3 consecutive minutes.

SEF484YB

DTC No.

Trouble diagnosis name

DTC detecting condition

Possible cause

P0420

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

P0420 THREE WAY CATALYST FUNCTION

EC-287

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NOTE:

Keep the vehicle speed as steady as possible during the cruising.

-

Stop vehicle with engine running.

NOTE:

Never turn ignition switch OFF.

3. Check 1st trip DTC.
Is the inspection result normal?

YES

>> Go to 

EC-287, "Diagnosis Procedure"

.

NO

>> INSPECTION END

Diagnosis Procedure

INFOID:0000000004349326

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-28, "IGNITION TIMING : Special Repair Requirement"

.

For specification, refer to 

EC-555, "Idle Speed"

 and 

EC-555, "Ignition Timing"

.

Is the inspection result normal?

YES

>> GO TO 5.

NO

>> Follow the 

EC-24, "BASIC INSPECTION : Special Repair Requirement"

.

5.

CHECK FUEL INJECTOR

1. Stop engine and then turn ignition switch ON.

JMBIA0163GB

EC-288

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P0420 THREE WAY CATALYST FUNCTION

2. Check the voltage between ECM harness connector and

ground.

Is the inspection result normal?

YES

>> GO TO 6.

NO

>> Perform 

EC-463, "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 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?

ECM

Ground

Voltage

Connector

Terminal

F14

29

Ground

Battery voltage

30

31

32

JMBIA1593GB

Spark should be generated.

JMBIA0066GB

Spark should be generated.