Nissan Frontier. Manual - part 591

IGNITION SIGNAL

EC-935

< DTC/CIRCUIT DIAGNOSIS >

[VQ40DE FOR USA AND CANADA]

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IGNITION SIGNAL

Component Description

INFOID:0000000009481643

IGNITION COIL & POWER TRANSISTOR

The ignition signal from the ECM is sent to and amplified by the power transistor. The power transistor turns

ON and OFF the ignition coil primary circuit. This ON/OFF operation induces the proper high voltage in the coil

secondary circuit.

Diagnosis Procedure

INFOID:0000000009481644

1.

CHECK ENGINE START

Turn ignition switch OFF, and restart engine.

Is engine running?
Yes or No

Yes (With CONSULT)>>GO TO 2.

Yes (Without CONSULT)>>GO TO 3.

No

>> GO TO 4.

2.

CHECK OVERALL FUNCTION

 With CONSULT

1. Perform “POWER BALANCE” in “ACTIVE TEST” mode with CONSULT.

2. Make sure that each circuit produces a momentary engine speed drop.
OK or NG

OK

>> INSPECTION END

NG

>> GO TO 10.

3.

CHECK OVERALL FUNCTION

 Without CONSULT

1. Let engine idle.

2. Read the voltage signal between ECM terminals 9, 10, 11, 13, 14, 15 and ground with an oscilloscope.

3. Verify that the oscilloscope screen shows the signal wave as shown below.

NOTE:

The pulse cycle changes depending on rpm at idle.

OK or NG

OK

>> INSPECTION END

NG

>> GO TO 10.

4.

CHECK IGNITION COIL POWER SUPPLY CIRCUIT-I

1. Turn ignition switch OFF, wait at least 10 seconds and then turn it ON.

2. Check voltage between ECM terminals 121 and ground with CONSULT or tester.

BBIA0561E

SEC986C

EC-936

< DTC/CIRCUIT DIAGNOSIS >

[VQ40DE FOR USA AND CANADA]

IGNITION SIGNAL

OK or NG

OK

>> GO TO 5.

NG

>> Go to 

EC-615, "Diagnosis Procedure"

.

5.

CHECK IGNITION COIL POWER SUPPLY CIRCUIT-II

1. Turn ignition switch OFF.

2. Disconnect condenser-1 harness connector.

3. Turn ignition switch ON.

4. Check voltage between condenser-1 terminal 1 and ground with CONSULT or tester.

OK or NG

OK

>> GO TO 8.

NG

>> GO TO 6.

6.

CHECK IGNITION COIL POWER SUPPLY CIRCUIT-III

1. Turn ignition switch OFF.

2. Disconnect IPDM E/R harness connector E119.

3. Check harness continuity between IPDM E/R terminal 3 and condenser-1 terminal 1.

Refer to Wiring Diagram.

4. Also check harness for short to ground and short to power.
OK or NG

OK

>> GO TO 17.

NG

>> GO TO 7.

7.

DETECT MALFUNCTIONING PART

Check the following.

• Harness connectors E2, F32

• Harness for open or short between condenser-1 and IPDM E/R

>> Repair open circuit or short to ground or short to power in harness or connectors.

8.

CHECK CONDENSER-1 GROUND CIRCUIT FOR OPEN AND SHORT

1. Turn ignition switch OFF.

2. Check harness continuity between condenser-1 terminal 2 and ground.

Refer to Wiring Diagram.

3. Also check harness for short to power.
OK or NG

OK

>> GO TO 9.

NG

>> Repair open circuit or short to power in harness or connectors.

Voltage: Battery voltage

BBIA0562E

Voltage: Battery voltage

Continuity should exist.

Continuity should exist.

IGNITION SIGNAL

EC-937

< DTC/CIRCUIT DIAGNOSIS >

[VQ40DE FOR USA AND CANADA]

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9.

CHECK CONDENSER-1

Refer to 

EC-938, "Component Inspection"

.

OK or NG

OK

>> GO TO 10.

NG

>> Replace condenser-1.

10.

CHECK IGNITION COIL POWER SUPPLY CIRCUIT-V

1. Turn ignition switch OFF.

2. Reconnect all harness connectors disconnected.

3. Disconnect ignition coil harness connector.

4. Turn ignition switch ON.

5. Check voltage between ignition coil terminal 3 and ground with CONSULT or tester.

OK or NG

OK

>> GO TO 12.

NG

>> GO TO 11.

11.

DETECT MALFUNCTIONING PART

Check the following.

• Harness connectors F26, F225

• Harness for open or short between ignition coil and harness connector F32

>> Repair or replace harness or connectors.

12.

CHECK IGNITION COIL GROUND CIRCUIT FOR OPEN AND SHORT

1. Turn ignition switch OFF.

2. Check harness continuity between ignition coil terminal 2 and ground.

Refer to Wiring Diagram.

3. Also check harness for short to power.
OK or NG

OK

>> GO TO 14.

NG

>> GO TO 13.

13.

DETECT MALFUNCTIONING PART

Check the following.

• Harness connectors F225, F26

• Harness for open or short between ignition coil and ground

>> Repair open circuit or short to power in harness or connectors.

14.

CHECK IGNITION COIL OUTPUT SIGNAL CIRCUIT FOR OPEN AND SHORT

1. Disconnect ECM harness connector.

2. Check harness continuity between ECM terminals 9, 10, 11, 13, 14, 15 and ignition coil terminal 1.

Voltage: Battery voltage

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Continuity should exist.

EC-938

< DTC/CIRCUIT DIAGNOSIS >

[VQ40DE FOR USA AND CANADA]

IGNITION SIGNAL

Refer to Wiring Diagram.

3. Also check harness for short to ground and short to power.
OK or NG

OK

>> GO TO 16.

NG

>> GO TO 15.

15.

DETECT MALFUNCTIONING PART

Check the following.

• Harness connectors F26, F225

• Harness for open or short between ignition coil and ECM

>> Repair open circuit or short to ground or short to power in harness or connectors.

16.

CHECK IGNITION COIL WITH POWER TRANSISTOR

Refer to 

EC-938, "Component Inspection"

.

OK or NG

OK

>> GO TO 17.

NG

>> Replace malfunctioning ignition coil with power transistor. Refer to 

EM-157, "Exploded View"

.

17.

CHECK INTERMITTENT INCIDENT

Refer to 

GI-42, "Intermittent Incident"

.

>> INSPECTION END

Component Inspection

INFOID:0000000009481645

IGNITION COIL WITH POWER TRANSISTOR

CAUTION:

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

1. Turn ignition switch OFF.

2. Disconnect ignition coil harness connector.

3. Check resistance between ignition coil terminals as follows.

4. If NG, Replace ignition coil with power transistor. Refer to 

EM-157, "Exploded View"

.

If OK, go to next step.

5. Turn ignition switch OFF.

6. Reconnect all harness connectors disconnected.

7. Remove fuel pump fuse (No.48) 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 procedure.

8. Start engine.

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

pressure.

10. Turn ignition switch OFF.

11. Remove ignition coil harness connectors to avoid the electrical

discharge from the ignition coils.

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

checked.

Continuity should exist.

Terminal No. (Polarity)

Resistance 

Ω [at 25°C (77°F)]

1 and 2

Except 0 or 

∞

1 and 3

Except 0

2 and 3

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