No.21 Engine Noise - Mazda 6 2002 Workshop Manual

STEP INSPECTION
4 Connect WDS or equivalent to DLC-2.
Retrieve any continuous memory, KOEO and
KOER DTCs.
Are there any DTCs displayed?
5 Verify test results.
• If okay, return to diagnostic inde to service any additional symptoms.
• If malfunction remains, replace PCM.
End Of Sie

NO.21 ENGINE NOISE

21 ENGINE NOISE
DESCRIPTION Engine noise from under hood
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
POSSIBLE CAUSE • Air leakage from intake-air system
• Improper variable air duct (VAD) control system operation
Rumble or grind noise:
• Improper drive belt tension
Rap or roar sound noise:
• Ehaust system looseness
Other noise:
• Camshaft friction gear noise or MLA noise
• Timing chain noise
Diagnostic procedure
STEP INSPECTION
1 Is squeal, click or chirp sound present?
2 Is rumble or grind sound present?
3 Is rattle sound present?
4 Is hiss sound present?
5 Is rap or roar sound present?
6 Is knock sound present?
7 Verify test results.
• If okay, return to diagnostic inde to service any additional symptoms.
• If malfunction remains, replace PCM.
End Of Sie
TROUBLESHOOTING
RESULTS
Yes DTC is displayed:
Go to appropriate DTC test.
No No DTC is displayed:
Inspect charcoal canister for fuel saturation.
If ecess amount of liquid fuel is present, replace
charcoal canister.
RESULTS
Yes Inspect engine oil level or drive belts.
No Go to net step.
Yes Inspect drive belts.
No Go to net step.
Yes Inspect location of rattle for loose parts.
No Go to net step.
Yes Inspect for following:
• Vacuum leakage
• Spark plug looseness
• Intake-air system leakage
• Variable air duct (VAD) control system operation
(See
Operation Inspection (L3 Engine
No Go to net step.
Yes Inspect ehaust system for loose parts.
No Go to net step.
Yes Go to symptom troubleshooting "No.11 Knocking/
pinging".
No If noise comes from engine internal, inspect for friction
gear, timing chain or MLA noise.
ACTION
ACTION
F–238 Variable Air Duct (VAD) Control System
Models).)
F
A6E398018881W23
F–219