Symptom Chart - NVH

WARNING: This page is about a different car, the 2010 Mercury Mariner and 2010 Ford Escape. However, it is still accessible from the selected car via links, so may be relevant.

NOTE: NVH symptoms should be identified using the diagnostic tools that are available. For a list of these tools, an explanation of their uses and a glossary of common terms, refer to NOISE, VIBRATION & HARSHNESS . Since it is possible any one of multiple systems may be the cause of a symptom, it may be necessary to use a process of elimination type of diagnostic approach to pinpoint the responsible system. If this is not the causal system for the symptom, refer back to NOISE, VIBRATION & HARSHNESS for the next likely system and continue diagnosis.

SYMPTOM CHART - NVH

Condition	Possible Sources	Action
Vibration when the brakes are applied	Brake disc (s)/drum(s) Suspension components	GO to PINPOINT TEST A .
Brake vibration/shudder - occurs when the brake pedal is released	Brake drag	GO to SYMPTOM CHART - BRAKE SYSTEM .
Rear brake noise - rotational chirp	Wheel cylinder(s)	LUBRICATE wheel cylinder(s). REFER to WHEEL CYLINDER LUBRICATION .
Rattling noise	Caliper guide pins or guide pin bolts	CHECK the caliper guide pins and guide pin bolts. REFER to BRAKE SYSTEM INSPECTION .
	Missing or damaged anti-rattle clips or springs	CHECK the brake pads for missing clips or broken springs. INSTALL new components as necessary. REFER to FRONT DISC BRAKE .
	Missing or damaged brake shoe hardware	CHECK the brake shoes for missing or broken hardware. INSTALL new components as necessary. REFER to DRUM BRAKE .
	Loose brake disc shield	TIGHTEN the brake disc shield bolts to specification. REFER to SPECIFICATIONS .
Squealing noise - occurs on first (morning) brake application	Brake pads/shoes	Acceptable condition. Caused by humidity and low brake pad temperature.
Squealing noise - a continuous squeal	Brake pads/shoes	INSPECT the brake pads/shoes. REFER to BRAKE SYSTEM INSPECTION .
Squealing noise - an intermittent squeal	Brake pads/shoes	Acceptable condition. Caused by cold, heat, water, mud or snow.
Groaning noise - occurs at low speeds with brake lightly applied (creeping)	Brake pads/shoes	Acceptable condition.
Grinding/moaning noise - continuous	Brake pads/shoes Brake disc/drums	INSPECT the brake pads/drums, brake discs/drums and attaching hardware for damage. VERIFY brake components are within specifications. REFER to BRAKE SYSTEM INSPECTION .
Excessive vacuum pump noise (above 60-70 dB)	Vacuum pump	INSTALL new vacuum pump as necessary.
Clicking noise (hybrid vehicles) - occurs when brake pedal is applied while the ignition is in the Key ON Engine OFF (KOEO)	Active brake booster	Acceptable condition.
Rumble/grinding noise - occurs while brakes are applied	ABS	Acceptable condition during an ABS or optimized hydraulic braking event.