Subaru Legacy BN/BS (2015-2019) Service Manual: Dtc p0506 idle control system rpm - lower than expected

Subaru Legacy BN/BS (2015-2019) Service Manual / Engine (diagnostics)(h6do) / Diagnostic procedure with diagnostic trouble code (dtc) / Dtc p0506 idle control system rpm - lower than expected

DTC DETECTING CONDITION:

Detected when two consecutive driving cycles with fault occur.

TROUBLE SYMPTOM:

• Hard to start the engine.

• Engine does not start.

• Improper idling

• Engine stalls.

CAUTION:

After servicing or replacing faulty parts, perform Clear Memory Mode Clear Memory Mode > OPERATION, and Inspection Mode Inspection Mode > PROCEDURE.

STEP	CHECK	YES	NO
1.CHECK FOR ANY OTHER DTC ON DISPLAY.	Is any other DTC displayed-	Check the appropriate DTC using the “List of Diagnostic Trouble Code (DTC)”. List of Diagnostic Trouble Code (DTC)	Diagnostic Procedure with Diagnostic Trouble Code (DTC) > DTC P0506 IDLE CONTROL SYSTEM RPM - LOWER THAN EXPECTED
2.CHECK AIR CLEANER ELEMENT. 1) Turn the ignition switch to OFF. 2) Check the air cleaner element.	Is there excessive clogging on air cleaner element-	Replace the air cleaner element. Air Cleaner Element	Diagnostic Procedure with Diagnostic Trouble Code (DTC) > DTC P0506 IDLE CONTROL SYSTEM RPM - LOWER THAN EXPECTED
3.CHECK ELECTRONIC THROTTLE CONTROL. 1) Remove the electronic throttle control. 2) Check the electronic throttle control.	Are foreign matter found inside electronic throttle control-	Remove foreign matter from electronic throttle control.	Perform the diagnosis of DTC P2101. Diagnostic Procedure with Diagnostic Trouble Code (DTC) > DTC P2101 THROTTLE ACTUATOR "A" CONTROL MOTOR CIRCUIT RANGE/PERFORMANCE

1. OUTLINE OF DIAGNOSIS

Detect the malfunction that actual engine speed is not close to target engine speed during idling. Judge as NG when actual engine speed is not close to target engine speed during idling.

2. EXECUTION CONDITION

Secondary Parameters	Execution condition
Battery voltage	≥ 10.9 V
Barometric pressure	≥ 75.1 kPa (563 mmHg, 22.2 inHg)
Lambda value (left and right)	≥ 0.85 and < 1.151
Vehicle speed	= 0 km/h (0 MPH)
Engine coolant temperature	≥ 60 °C (140 °F)
Elapsed time after starting the engine	≥ 10 s
Accelerator pedal position	= 0%
Elapsed time after switching neutral position switch to ON/OFF	> 5 s
Cold start diagnosis	Not in operation

3. GENERAL DRIVING CYCLE

Perform the diagnosis continuously at idling after warming up engine.

4. DIAGNOSTIC METHOD

If the duration of time while the following conditions are met is longer than the time indicated, judge as NG.

Judgment Value

Malfunction Criteria	Threshold Value
Actual engine speed − Targeted engine speed	< −100 rpm

Time Needed for Diagnosis: 15 s - 1 time(s)

Malfunction Indicator Light Illumination: Illuminates when malfunction occurs in 2 continuous driving cycles.

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Other materials:

Inspection
1. Check the spark plug for abnormalities. If defective, replace the spark plug.(A)Terminal damage(B)Crack or damage in insulator(C)Damaged gasket2. Check the spark plug electrode and condition of the insulator. If abnormal, check and repair the cause and replace the spark plug.(1) Normal:Brown to g ...