Nissan Frontier D22. Manual - part 596

DTC P0420, P0430 THREE WAY CATALYST FUNCTION

EC-1487

[VG33ER]

C

D

E

F

G

H

I

J

K

L

M

A

EC

7.

Make sure that the voltage switching frequency (high & low)
between ECM terminals 56 and engine ground, or 57 and
engine ground is very less than that of ECM terminals 50 and
engine ground, or 51 and engine ground.
Switching frequency ratio = A/B
A: Heated oxygen sensor 2 voltage switching frequency
B: Heated oxygen sensor 1 voltage switching frequency
This ratio should be less than 0.75.
If the ratio is greater than above, it means three way catalyst
(manifold) does not operate properly. Go to 

EC-1488, "Diagnos-

tic Procedure"

 .

NOTE:
If the voltage at terminal 50 or 51 does not switch periodically more than 5 times within 10 seconds at step 5,
perform trouble diagnosis for DTC P0133, P0153 first. (See 

EC-1384

 .)

SEF442V

EC-1488

[VG33ER]

DTC P0420, P0430 THREE WAY CATALYST FUNCTION

Diagnostic Procedure

UBS00DXE

1. 

CHECK EXHAUST SYSTEM

Visually check exhaust tubes and muffler for dent.

OK or NG

OK

>> GO TO 2.

NG

>> Repair or replace it.

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).

OK or NG

OK

>> GO TO 3.

NG

>> Repair or replace.

3. 

CHECK INTAKE AIR LEAK

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

OK or NG

OK

>> GO TO 4.

NG

>> Repair or replace.

4. 

CHECK IGNITION TIMING

Check the following items. Refer to 

EC-1247, "Basic Inspection"

 .

OK or NG

OK

>> GO TO 5.

NG

>> Adjust ignition timing.

SEC502D

Items

Specifications

Ignitions timing

10

° ± 5° BTDC

Base idle speed

700 

± 50 rpm (in P or N position)

 Closed throttle position switch idle 
position adjustment

Feeler gauge thickness and switch 
condition
0.3 mm (0.012 in): ON
0.4 mm (0.016 in): OFF

Target idle speed

750 

± 50 rpm (in P or N position)

DTC P0420, P0430 THREE WAY CATALYST FUNCTION

EC-1489

[VG33ER]

C

D

E

F

G

H

I

J

K

L

M

A

EC

5. 

CHECK INJECTORS

1.

Refer to 

EC-1717, "Wiring Diagram"

2.

Stop engine and then turn ignition switch ON.

3.

Check voltage between ECM terminals 102, 104, 106, 109, 111
and 113 and ground with CONSULT-II or tester.

OK or NG

OK

>> GO TO 6.

NG

>> Perform 

EC-1716, "INJECTOR CIRCUIT"

6. 

CHECK IGNITION SPARK

1.

Turn ignition switch OFF.

2.

Disconnect ignition wire from spark plug.

3.

Connect a known good spark plug to the ignition wire.

4.

Place end of spark plug against a suitable ground and crank engine.

5.

Check for spark.

OK or NG

OK

>> GO TO 8.

NG

>> GO TO 7.

7. 

CHECK IGNITION WIRES

1.

Inspect wires for cracks, damage, burned terminals and for improper fit.

2.

Measure the resistance of wires to their distributor cap terminal.
Move each wire while testing to check for intermittent breaks.
Resistance:

If the resistance exceeds the above specification, inspect ignition wire to distributor cap connection. Clean
connection or replace the ignition wire with a new one.

OK or NG

OK

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

EC-1710, "IGNITION SIGNAL"

 .

NG

>> Replace.

Battery voltage should exist.

SEF711U

SEF282G

Cylinder No.

Resistance k

Ω [at 25°C (77°F)]

1

Approx. 6.5

2

Approx. 10.0

3

Approx. 8.5

4

Approx. 12.5

5

Approx. 8.5

6

Approx. 11.0

SEF174P

EC-1490

[VG33ER]

DTC P0420, P0430 THREE WAY CATALYST FUNCTION

8. 

CHECK INJECTOR

1.

Turn ignition switch OFF.

2.

Remove injector assembly.
Refer to 

EM-80, "OUTER COMPONENT PARTS"

 .

Keep fuel hose and all injectors connected to injector gallery.

3.

Disconnect all ignition coil harness connectors.

4.

Turn ignition switch ON.
Make sure fuel does not drip from injector.

OK or NG

OK (Does not drip)>>GO TO 9.
NG (Drips)>>Replace the injector(s) from which fuel is dripping.

9. 

CHECK INTERMITTENT INCIDENT

Refer to 

EC-1297, "TROUBLE DIAGNOSIS FOR INTERMITTENT INCIDENT"

 .

Trouble is fixed>>INSPECTION END.
Trouble is not fixed>>Replace three way catalyst (manifold).