Infiniti G35 (V35) Sedan. Manual - part 546

EC-330

< COMPONENT DIAGNOSIS >

[VQ35HR]

P0506 ISC SYSTEM

P0506 ISC SYSTEM

Description

INFOID:0000000000956708

The ECM controls the engine idle speed to a specified level through the fine adjustment of the air, which is let
into the intake manifold, by operating the electric throttle control actuator. The operating of the throttle valve is
varied to allow for optimum control of the engine idling speed. The crankshaft position sensor (POS) detects
the actual engine speed and sends a signal to the ECM.
The ECM controls the electric throttle control actuator so that the engine speed coincides with the target value
memorized in the ECM. The target engine speed is the lowest speed at which the engine can operate steadily.
The optimum value stored in the ECM is determined by taking into consideration various engine conditions,
such as during warming up, deceleration, and engine load (air conditioner, power steering and cooling fan
operation, etc.). 

DTC Logic

INFOID:0000000000956709

DTC DETECTION LOGIC

NOTE:
If DTC P0506 is displayed with other DTC, first perform the trouble diagnosis for the other DTC.

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.
If the target idle speed is out of the specified value, perform 

EC-18, "IDLE AIR VOLUME LEARNING :

Special Repair Requirement"

, before conducting DTC Confirmation Procedure.

TESTING CONDITION:
• Before performing the following procedure, confirm that battery voltage is more than 11V at idle.
• Always perform the test at a temperature above 

−

10

°

C(14

°

F).

>> GO TO 2.

2.

PERFORM DTC CONFIRMATION PROCEDURE

1.

Start engine and warm it up to normal operating temperature.

2.

Turn ignition switch OFF and wait at least 10 seconds.

3.

Restart engine and run it for at least 1 minute at idle speed.

4.

Check 1st trip DTC.

Is 1st trip DTC detected?

YES

>> Go to 

EC-330, "Diagnosis Procedure"

.

NO

>> INSPECTION END

Diagnosis Procedure

INFOID:0000000000956710

1.

CHECK INTAKE AIR LEAK

1.

Start engine and let it idle.

2.

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

Is intake air leak detected?

YES

>> Discover air leak location and repair.

NO

>> GO TO 2.

2.

REPLACE ECM

1.

Stop engine.

DTC No.

Trouble diagnosis name

DTC detecting condition

Possible cause

P0506

Idle speed control sys-
tem RPM lower than ex-
pected

The idle speed is less than the target idle speed 
by 100 rpm or more.

• Electric throttle control actuator
• Intake air leak

P0506 ISC SYSTEM

EC-331

< COMPONENT DIAGNOSIS >

[VQ35HR]

C

D

E

F

G

H

I

J

K

L

M

A

EC

N

P

O

2.

Replace ECM.

3.

Go to 

EC-15, "ADDITIONAL SERVICE WHEN REPLACING CONTROL UNIT : Special Repair Require-

ment"

.

>> INSPECTION END

EC-332

< COMPONENT DIAGNOSIS >

[VQ35HR]

P0507 ISC SYSTEM

P0507 ISC SYSTEM

Description

INFOID:0000000000956711

The ECM controls the engine idle speed to a specified level through the fine adjustment of the air, which is let
into the intake manifold, by operating the electric throttle control actuator. The operating of the throttle valve is
varied to allow for optimum control of the engine idling speed. The crankshaft position sensor (POS) detects
the actual engine speed and sends a signal to the ECM.
The ECM controls the electric throttle control actuator so that the engine speed coincides with the target value
memorized in the ECM. The target engine speed is the lowest speed at which the engine can operate steadily.
The optimum value stored in the ECM is determined by taking into consideration various engine conditions,
such as during warming up, deceleration, and engine load (air conditioner, power steering and cooling fan
operation, etc.). 

DTC Logic

INFOID:0000000000956712

DTC DETECTION LOGIC

NOTE:
If DTC P0507 is displayed with other DTC, first perform the trouble diagnosis for the other DTC.

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.
If the target idle speed is out of the specified value, perform 

EC-18, "IDLE AIR VOLUME LEARNING :

Special Repair Requirement"

, before conducting DTC Confirmation Procedure.

TESTING CONDITION:
• Before performing the following procedure, confirm that battery voltage is more than 11V at idle.
• Always perform the test at a temperature above 

−

10

°

C(14

°

F).

>> GO TO 2.

2.

PERFORM DTC CONFIRMATION PROCEDURE

1.

Start engine and warm it up to normal operating temperature.

2.

Turn ignition switch OFF and wait at least 10 seconds.

3.

Start engine and run it for at least 1 minute at idle speed.

4.

Check 1st trip DTC.

Is 1st trip DTC detected?

YES

>> Go to 

EC-332, "Diagnosis Procedure"

.

NO

>> INSPECTION END

Diagnosis Procedure

INFOID:0000000000956713

1.

CHECK PCV HOSE CONNECTION

Confirm that PCV hose is connected correctly.

Is the inspection result normal?

YES

>> GO TO 2.

NO

>> Repair or replace.

2.

CHECK INTAKE AIR LEAK

1.

Start engine and let it idle.

2.

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

DTC No.

Trouble diagnosis name

DTC detecting condition

Possible cause

P0507

Idle speed control sys-
tem RPM higher than 
expected

The idle speed is more than the target idle 
speed by 200 rpm or more.

• Electric throttle control actuator
• Intake air leak
• PCV system

P0507 ISC SYSTEM

EC-333

< COMPONENT DIAGNOSIS >

[VQ35HR]

C

D

E

F

G

H

I

J

K

L

M

A

EC

N

P

O

Is intake air leak detected?

YES

>> Discover air leak location and repair.

NO

>> GO TO 3.

3.

REPLACE ECM

1.

Stop engine.

2.

Replace ECM.

3.

Go to 

EC-15, "ADDITIONAL SERVICE WHEN REPLACING CONTROL UNIT : Special Repair Require-

ment"

.

>> INSPECTION END