NO.21 ENGINE NOISE [AJ]


21	Engine noise
DESCRIPTION	• Engine noise from under hood
POSSIBLE CAUSE	Squeal, click or chirp noise: • Improper engine oil level • Improper drive belt tension Rattle sound noise: • Loose parts Hiss sound noise: • Vacuum leakage • Loose spark plug • Air leakage from intake-air system Rumble or grind noise: • Improper drive belt tension Rap or roar sound noise: • Exhaust system looseness Other noise: • Camshaft friction gear noise or HLA noise


STEP	INSPECTION		ACTION
1	• Is squeal, click or chirp sound present?	Yes	Inspect the engine oil level or the drive belts.
1	• Is squeal, click or chirp sound present?	No	Go to the next step.
2	• Is rumble or grind sound present?	Yes	Inspect the drive belt.
2	• Is rumble or grind sound present?	No	Go to the next step.
3	• Is rattle sound present?	Yes	Inspect location of rattle for loose parts.
3	• Is rattle sound present?	No	Go to the next step.
4	• Is hiss sound present?	Yes	Inspect for the following: • Vacuum leakage • Spark plug loose • Intake-air system leakage
4	• Is hiss sound present?	No	Go to the next step.
5	• Is rap or roar sound present?	Yes	Inspect the exhaust system for loose parts.
5	• Is rap or roar sound present?	No	Go to the next step.
6	• Is knock sound present?	Yes	Go to symptom troubleshooting "No.13 Knocking/ pinging". (See NO.13 KNOCKING/PINGING-ACCELERATION/CRUISE [AJ].)
6	• Is knock sound present?	No	If noise comes from engine internal, inspect for friction gear or HLA noise.
7	• Verify test results. - If normal, return to diagnostic index to service any additional symptoms. - If malfunction remains, inspect related Service Information and perform repair or diagnosis. • If vehicle is repaired, troubleshooting completed. • If vehicle is not repaired or additional diagnostic information is not available, replace or reprogram the PCM.