Nissan Titan. Manual - part 262
P0506 ISC SYSTEM
EC-349
< DTC/CIRCUIT DIAGNOSIS >
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P0506 ISC SYSTEM
Description
INFOID:0000000009886761
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:0000000009886762
DTC Confirmation Procedure
INFOID:0000000009886763
NOTE:
• If DTC Confirmation Procedure has been previously conducted, always perform the following before con-
ducting the next step.
• If the target idle speed is out of the specified value, perform
EC-129, "Idle Air Volume Learning"
,
before conducting DTC Confirmation Procedure. For the target idle speed, refer to the
1. Turn ignition swich OFF and wait at least 10 seconds.
2. Turn ignition swich ON.
3. Turn ignition swich OFF and wait at least 10 seconds.
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).
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. Start engine and run it for at least 1 minute at idle speed.
5. Check 1st trip DTC.
6. If 1st trip DTC is detected, go to
Diagnosis Procedure
INFOID:0000000009886764
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.
OK or NG
OK
>> GO TO 2.
NG
>> Discover air leak 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-7, "ECM RE-COMMUNICATING FUNCTION : Special Repair Requirement"
.
4. Perform
5. Perform
EC-128, "Accelerator Pedal Released Position Learning"
.
DTC No.
Trouble diagnosis name
DTC detecting condition
Possible cause
P0506
0506
Idle speed control system
RPM lower than expected
The idle speed is less than the target idle speed
by 100 rpm or more.
• Electric throttle control actuator
• Intake air leak