Diagnostic Procedure

NO. 21 ENGINE NOISE (SKYACTIV-G 2.5T) DIAGNOSTIC PROCEDURE

STEP	INSPECTION	RESULTS	ACTION
1	VERIFY SYMPTOM Verify the occurring sound.	-	Buzzing sound is heard from exhaust pipe during cold engine start: Go to the next step. Squeal, click, or chirp sound is heard: Go to Step 3. Thumping/rattling or creaking sound is heard: Go to Step 4. Hissing sound is heard: Go to Step 5. Clattering sound is heard: Go to Step 6. Lightly tapping or rumbling sound is heard: Go to Step 7. Excessive noise from turbocharger: Go to Step 8. Other noise is heard: Go to Step 10.
2	BUZZING SOUND IS HEARD FROM EXHAUST PIPE DURING COLD ENGINE START Verify the sound from the exhaust pipe during a cold engine start. Does the sound disappear after approx. 30 s have elapsed?	Yes	NOTE: During a cold engine start, sound occurs for up to approx. 30 s with fast idle up for a drive-by-wire control and the warm-up promotion spark retard correction for ignition timing control. Go to Step 9 because the operation is normal.
2		No	Inspect the following: Exhaust system installation condition Intake system installation condition If there is any malfunction: Repair or replace the malfunctioning part according to the inspection results. If there is no malfunction: Go to Step 12.
3	VERIFY IF THERE IS SQUEAL, CLICK, OR CHIRP SOUND Inspect the following: Engine oil level Solenoid valves installation Drive belt tension Generator installation Auto tensioner bearing damaged Splash shield or under cover loose Is there any malfunction?	Yes	Repair or replace the malfunctioning part according to the inspection results.
3		No	Go to Step 12.
4	VERIFY IF THERE IS THUMPING/RATTLING OR CREAKING SOUND Inspect the following: Drive belt tension Loose parts in engine compartment Loose fitting heater hoses vibrating the heater hose bracket protector Is there any malfunction?	Yes	Repair or replace the malfunctioning part according to the inspection results.
4		No	Go to Step 12.
5	VERIFY IF THERE IS HISSING SOUND Inspect the following: Vacuum leakage Spark plug loose Intake-air system leakage Is there any malfunction?	Yes	Repair or replace the malfunctioning part according to the inspection results.
5		No	Go to Step 12.
6	VERIFY IF THERE IS CLATTERING SOUND Inspect the location of rattle for loose parts. Is there any malfunction?	Yes	Repair or replace the malfunctioning part according to the inspection results.
6		No	Go to Step 12.
7	VERIFY IF THERE IS LIGHTLY TAPPING OR RUMBLING SOUND Inspect the following: Exhaust system installation condition Intake system installation condition Is there any malfunction?	Yes	Repair or replace the malfunctioning part according to the inspection results.
7		No	Go to Step 12.
8	VISUALLY INSPECT THE TURBOCHARGER Remove the parts necessary to inspect the turbocharger without removing the turbocharger. Inspect if the turbocharger compressor wheel is bent, damaged, or interfering with housing on vehicle. Is there any malfunction?	Yes	Repair or replace the malfunctioning part according to the inspection results.
8		No	Go to next Step.
9	VISUALLY INSPECT THE TURBINE HOUSING Visually inspect the turbine housing. Is there any carbon built-up or foreign material on the turbine housing?	Yes	Clean built-up carbon or remove foreign materials. If turbine housing damaged: Replace the dynamic pressure turbo. (See Dynamic Pressure Turbo Removal/Installation .)
9		No	Replace the intake air system. (See Intake-Air System Removal/Installation .)
10	VERIFY IF THERE IS KNOCK SOUND Is knocking noise present?	Yes	Perform the symptom troubleshooting "NO. 13 KNOCKING/PINGING-ACCELERATION/CRUISE". (See NO. 13 Knocking/Pinging-acceleration/Cruise .)
10	VERIFY IF THERE IS KNOCK SOUND Is knocking noise present?	No	If noise comes from engine internal: Inspect the following: Timing chain Hydraulic lash adjuster (HLA) noise Electric variable valve timing actuator Hydraulic variable valve timing actuator Engine compression Repair or replace the malfunctioning part according to the inspection results.
11	Verify the test results. If normal, return to the diagnostic index to service any additional symptoms. (See Symptom Diagnostic Index .) If a malfunction remains, inspect the related Service Information and perform the repair or diagnosis. If the vehicle is repaired, troubleshooting is completed. If the vehicle is not repaired or additional diagnostic information is not available, replace the PCM. (See PCM Removal/Installation .)