Nissan Sentra B18 (2020-2025) Service Manual: P0506 Isc System

Dtc 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

POSSIBLE CAUSE

• Electric throttle control actuator

• Intake air leaks

FAIL-SAFE

Not applicable

Confirmation Procedure

1. CHECK DTC PRIORITY

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

   Is applicable DTC detected?

   YES >>

   Perform diagnosis of applicable. Refer to DTC Index.

   NO >>

   GO TO 2.

2. PRECONDITIONING

   If DTC Confirmation Procedure has been previously conducted, always perform the following procedure before conducting the next test. When the target idle speed is not the specified value, refer to IDLE SPEED : Periodic Maintenance. before conducting DTC Confirmation Procedure.

   TESTING CONDITION:

   • Before performing the following procedure, confirm that battery voltage is 11 V or more at idle.

   • Always perform at a temperature above −10°C (14°F).

   Note:

   In the highlands of over 2,400m altitude, DTC may be detected without abnormality, but that case is not abnormal if the DTC is not detected when "DTC confirmation procedure" is performed at under 2,400m altitude.

   >>

   GO TO 3.

3. PERFORM DTC CONFIRMATION PROCEDURE

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

   2. Turn ignition switch OFF and wait at least 10 seconds.

   3. Start the engine and let it idle for at least 1 minute.

   4. Check 1st trip DTC.

   Is 1st trip DTC detected?

   YES >>

   Refer to DTC Diagnosis Procedure.

   NO-1 >>

   To check malfunction symptom before repair: Refer to Intermittent Incident.

   NO-2 >>

   Confirmation after repair: INSPECTION END

Dtc Diagnosis Procedure

1. CHECK DTC PRIORITY

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

   Is applicable DTC detected?

   YES >>

   Perform diagnosis of applicable. Refer to DTC Index.

   NO >>

   GO TO 2.

2. CHECK INTAKE AIR LEAK

   1. Start the engine and let it idle.

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

   Is the inspection result normal?

   YES >>

   GO TO 3.

   NO >>

   Repair or replace malfunctioning part.

3. REPLACE ECM

   1. Stop the engine.

   2. Replace ECM. Refer to ECM : Removal & Installation.

   >>

   INSPECTION END

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