Description
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 DETECTION LOGIC
NOTE: If DTC P0507 is displayed with other DTC, first perform the trouble diagnosis for the other DTC.
| DTC No. | Trouble diagnosis name | DTC detecting condition | Possible cause |
| P0507 | ISC SYSTEM (Idle speed control system RPM higher than expected) | The idle speed is more than the target idle speed by 200 rpm or more. |
|
DTC CONFIRMATION PROCEDURE
1.PRECONDITIONING
If DTC Confirmation Procedure has been previously conducted, always perform the following procedure before conducting the next test.
If the target idle speed is out of the specified value, perform EC, "Work Procedure", before conducting DTC Confirmation Procedure.
TESTING CONDITION:
>> GO TO 2.
2.PERFORM DTC CONFIRMATION PROCEDURE
Is 1st trip DTC detected?
YES >> Proceed to EC, "Diagnosis Procedure".
NO >> INSPECTION END
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 errordetected parts.
2.CHECK INTAKE AIR LEAK
Is intake air leak detected?
YES >> Discover air leak location and repair.
NO >> Replace ECM. Refer to EC, "Removal and Installation".
P0506 ISC systemDescription 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 ac ...

Description ECM controls ignition timing and engine idle speed when engine is started with prewarming up condition. This control promotes the activation of three way catalyst by heating the c ...
When traveling or registering in another country
When planning to drive your NISSAN vehicle
in another country, you should first find
out if the fuel available is suitable for your vehicle's
engine.
Using fuel with an octane rating that is too low
may cause engine damage. All gasoline vehicles
must be operated with unleaded gasoline. There ...
Electric ignition system
ELECTRIC IGNITION SYSTEM : System Diagram
ELECTRIC IGNITION SYSTEM : System Description
INPUT/OUTPUT SIGNAL CHART
Sensor
Input signal to ECM
ECM function
Actuator
Crankshaft position sensor (POS)
Engine speed*3
Piston position
Ignition timing control
Igni ...