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EC-772 < COMPONENT DIAGNOSIS > [VK56DE] P0506 ISC SYSTEM P0506 ISC SYSTEM Description INFOID:0000000005257743 NOTE: If DTC P0506 is displayed with other DTC, first perform the trouble diagnosis for the other DTC. 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.). On Board Diagnosis Logic INFOID:0000000005257744 DTC Confirmation Procedure INFOID:0000000005257745 NOTE: • If the target idle speed is out of the specified value, perform EC-511, "Idle Air Volume Learning" , before conducting DTC Confirmation Procedure. For the target idle speed, refer to . • If DTC Confirmation Procedure has been previously conducted, always perform the following procedure before conducting the next test. 1. Turn ignition switch OFF and wait at least 10 seconds. 2. Turn ignition switch ON. 3. Turn ignition switch OFF and wait at least 10 seconds. TESTING CONDITION: • Before performing the following procedure, confirm that battery voltage is more than 11 V at idle. • Always perform the test at a temperature above − 10 ° C(14 ° F). 1. Open engine hood. 2. Start engine and warm it up to normal operating temperature. 3. Turn ignition switch OFF and wait at least 10 seconds. 4. Turn ignition switch ON. 5. Turn ignition switch OFF and wait at least 10 seconds. 6. Start engine and run it for at least 1 minute at idle speed. 7. Check 1st trip DTC. 8. If 1st trip DTC is detected, go to Diagnosis Procedure INFOID:0000000005257746 1. CHECK INTAKE AIR LEAKAGE 1. Start engine and let it idle. 2. Listen for an intake air leakage after the mass air flow sensor. OK >> GO TO 2. NG >> Discover air leakage location and repair. 2. REPLACE ECM 1. Stop engine. 2. Replace ECM. 3. Perform initialization of NVIS(NATS) system and registration of all NVIS(NATS) ignition key IDs. Refer to SEC-10, "ECM RE-COMMUNICATING FUNCTION : Special Repair Requirement" DTC No. Trouble diagnosis name DTC detecting condition Possible cause P0506 Idle speed control system The idle speed is less than the target idle speed • Electric throttle control actuator 2010 Pathfinder |