Noise, Vibration and Harshness (NVH) Diagnostics and Testing (General information / Using the manual / Ford Focus 1 1998-2004)

Inspection and verification

1. Check the validity of the customer's complaint.
2. Visually inspect for obvious signs of mechanical or electrical damage.
3. If an obvious cause for the problem you have identified or the customer has described is found, correct it (if possible) before proceeding with further actions.
4. If the problem is not visually obvious, check the symptom and refer to the Symptom Table.

Methodology for using this section of diagnostic procedures

Noise, vibration and harshness (NVH) issues have become very important as vehicles become more susceptible to such influences. This section will help identify such situations.
This section provides information on diagnostic procedures based on a specific symptom of a malfunction. If, for example, the problem occurs at high vehicle speeds, the "Shaking and Vibration at High Speed" chapter is the best place to begin diagnostics.
The road test procedure will tell you how to classify conditions into categories and how to distinguish vibration from shaking.
To ensure that the cause is either identified or corrected, a series of quick checks are carried out during the road test.
Decide on the name of the condition, go to the appropriate section and find the correct diagnostic method. Once the condition is identified, the job is partially done.
Follow the prescribed diagnostic procedure.
Quick checks are described within a separate step, while the more complex checks and adjustments are described in the General Procedures chapter.
Always follow the sequence of each step exactly and make notes so that you can track any important points later.

Customer survey

A road test and customer interview (if possible) will provide information that will help identify the problem and indicate where best to begin diagnostics.

State identification

Noise, vibration and harshness (NVH) typically manifests itself in four zones:

tires
engine accessories
suspension
transmission

Therefore, it is necessary to narrow down the NVH problem to these specific areas as much as possible. The easiest and fastest way to do this is to perform the prescribed road test. To facilitate the diagnostic procedures and checks, use a certified tester for diagnosing NVH problems.

Noise diagnostic procedure

Noise not related to vehicle axles

The five most common sources of non-axle noise are the exhaust system, tires, roof rack, trim panels, and transmission.

Therefore, before disassembling and diagnosing the transmission, make sure that the noise is not caused by any of the following conditions.

Under certain conditions, exhaust emissions can produce a sound that closely resembles a "mechanical" noise. In other cases, it can be mistaken for wheel bearings rattling.
Tires, especially winter tires, can cause a high-pitched whine or roar from the treads, similar to a "mechanical" noise. Radial tires have this characteristic to some extent. In addition, non-standard tires with an unusual tread pattern can also cause a whine or roar.
Trim panels may also produce whistling or howling noises.
A dull metallic sound may be heard when shifting into R or D on an automatic transmission or when applying or releasing the throttle. The noise may be caused by side play in the transmission.
A rattling noise in the bearings is similar to the sound of marbles colliding. This condition is usually caused by wheel bearing failure.

Noises

"Mechanical" noise is usually a roaring or whining sound caused by damage to the mechanism or improper bearing preload. It can occur at various speeds and driving conditions. It can also be a constant noise.
"Clucking" is a distinct rattling noise that sounds like a stick caught in the spokes of a rapidly spinning bicycle wheel. It occurs when decelerating from 64 km/h (40 mph), and can usually be heard throughout the entire deceleration to a complete stop. The frequency varies with the speed of the vehicle.
The knocking sound is very similar to a "clucking" sound, although it may be quieter. It occurs when accelerating or decelerating. Disassembling it will show what needs to be fixed.

Clicking, popping or grinding noises may be caused by:

wear, damage or improper installation of wheel bearings, suspension components or the brake system.

Before disassembling the transaxle to diagnose and eliminate "mechanical" noise, inspect the tires, exhaust system, and trim.

The noises described in the Road Test chapter usually have specific causes that can be diagnosed by observing the unit as it is disassembled. The primary clues are the nature of the noise heard during the road test and the driving conditions.

Vibration

Vibration at high speeds can be caused by the following:

imbalance of the front or rear wheels;
deviation of the tire shape from the circular shape (ovality).

Vibration, shaking during acceleration can be caused by the following:

damage to the powertrain/transmission mounts;
exceeding the operating angles in constant velocity joints (CV joints): this is caused by incorrect ground clearance; Check the ground clearance, correct spring characteristics and components in a non-working condition.

Road test

Any mechanically driven component will produce some noise when in operation. Some noise is normal and can be heard at certain speeds or under certain driving conditions, such as driving on newly paved roads. Minor noise is not an indication of a malfunction and can be considered normal.

A road test and customer interview (if possible) will provide information that will help identify the problem and suggest where to begin diagnostics.

1. Take notes during the diagnostic process. Write down even the smallest information, because things may turn out so that this information becomes the most important information.
2. Do not touch anything until you have road tested the vehicle and performed a thorough visual inspection. Leave the tire pressure and vehicle load as they were when the fault condition was first observed. Adjusting the tire pressure, vehicle load, or making other adjustments may reduce the "intensity" of the problem condition to a level where the problem can no longer be clearly identified. It may also introduce something new into the system that prevents proper diagnosis.
3. Perform a visual inspection (part of the preliminary diagnosis), writing down anything that seems wrong. RECORD the tire pressure, but do not adjust it yet. RECORD any leaks, loose nuts and bolts, areas where components may rub against each other. Check the cargo area for unusual items.
4. Perform a road test to determine the nature of the fault by reproducing the problem condition multiple times.
5. Once the condition has been reproduced, perform quick tests. This will help identify the correct diagnostic procedure. To ensure that the quick tests are giving the correct result, perform them several times. Remember that quick tests performed during a road test will not tell you what the problem is (where), but they will show you where it is not.

Quick checks performed during a road test

1. At 24-80 km/h (15-50 mph): A groaning noise is heard under light acceleration and vibration may be felt in the front floor area. The situation is usually worse when accelerating at this speed at certain engine speeds and throttle positions. A groaning noise may be present, the nature of which depends on the component causing the noise. Refer to the Symptom Chart, chapter "Variable Pitch Groaning Noise".

2. Acceleration/Deceleration: When accelerating or decelerating slowly, a shaking sound may sometimes be felt in the steering wheel/column, seats, front floor, front door trim panels, or front body panels. This is a low frequency vibration (approximately 9 to 15 cycles per second). It may or may not increase with light application of the brakes. Refer to the Symptom Chart, Humming/Shaking/Vibration at Idle.

3. High Speed: Vibration is felt without visible shaking in the front floor or seats, but is accompanied by a rumbling, humming, buzzing noise. Coast with the clutch pedal depressed (manual transmission) or the gearshift lever in neutral (automatic transmission) or with the engine idling. If vibration is still present, it is related to the wheels, tires, front brake discs, wheel hubs, or front wheel bearings. Refer to the Symptom Chart, chapter "Shaking and Vibration at High Speed.".

4. Sensitivity to engine speed: The vibration is felt whenever the engine reaches a certain speed. It will disappear when coasting in neutral. The vibration can also be reproduced with the vehicle stationary by bringing the engine speed up to the problem speed. It can be caused by anything from the accessory drive belt to the clutch or torque converter, which rotate at engine speed when the vehicle is stationary. Refer to the Symptom Chart, chapter "Shaking and Vibration While Driving.".

5. Noise and vibration when cornering: Clicking, popping or grinding noises may be caused by the following:

wear, damage or improper installation of front wheel bearings;
damage to the powertrain/transmission supports.

Road conditions

An experienced technician will always have a route that he will use for all road tests when diagnosing NVH. The road chosen should be reasonably smooth, level, and free of bumps and ruts (unless a specific problem condition is to be identified). A smooth asphalt road is preferable, allowing testing over the entire speed range. Gravel and bumpy, shaky roads are not suitable, as they add additional noise. Once a route has been developed and consistently used, the road noise component can be isolated from the test results.

NOTE: Some problem conditions may only occur on smooth asphalt roads.

If the customer complains about noise or vibration on a specific road and only on that road, the road surface may be the source of the concern. If possible, try to test the car on the same type of road.

Preparing the car

Before performing a road test, perform a thorough exterior inspection. NOTE anything unusual. If the vehicle is functional and the fault cannot cause mechanical damage, do not touch (service, adjust) anything until the road test.

After confirming that the fault has been corrected, make sure that all components removed during repair are reinstalled.

State	Possible Causes	Action
• Shaking and vibration when moving	• Vibration of the front of the car • Engine/gearbox.	• Proceed to PINPOINT TEST A
• A moaning sound of variable pitch	• Air filter • Power Assisted Steering (PAS). • Power unit • Powertrain/transmission mounts • Exhaust system	• Proceed to PINPOINT TEST B
• Humming/shaking/vibrating or jerking when idling	• Ropes/cables/hoses • Powertrain/transmission mounts • Exhaust system • Drive belts/pulleys	• Proceed to PINPOINT TEST C
• Front end vibration analysis	• Suspension • Wheel bearings	• Proceed to PINPOINT TEST D
• Noise not related to the bridge	• Trim panels. • Air conditioning system • Accessories	• Proceed to PINPOINT TEST E

Pinpoint - tests

NOTE: Pinpoint tests are designed to help the technician perform a step-by-step diagnostic procedure to ultimately determine the cause of a problem condition. It is not always necessary to follow the chart to the end. Perform only those Pinpoint test steps that are necessary to correct the problem. Then test the system to ensure that everything is OK.

After confirming that the fault has been corrected, make sure that all components removed during repair are reinstalled.

PINPOINT TEST A: SHAKING AND VIBRATION WHEN MOVING

STATES	DETAILS/RESULTS/ACTIONS
A1: COASTING IN NEUTRAL
	1Perform a test during which the vehicle should move by inertia in neutral gear.
	• Does the vibration disappear when the car is coasting in neutral gear?
	→ Yes
	Go to A2
	→ No
	Proceed to Pinpoint Test D.
A2: CHECKING THE POWERTRAIN/TRANSMISSION MOUNTS IN THE DRIVE AXLE BLOCK
	1Visually CHECK the condition of the hydraulic mounts of the power unit/gearbox in the block with the drive axle and the presence of leaks in them.
	• Are the powertrain/gearbox mounts in the block with the drive axle in order?
	→ Yes
	Go to A3
	→ No
	Proceed to Pinpoint Test D.
A3: CHECKING THE ALIGNMENT OF THE POWERTRAIN/TRANSMISSION MOUNTS IN THE DRIVE AXLE BLOCK
	1Perform the engine/transaxle mount alignment procedure described in this section.
	• Has shaking and vibration been eliminated?
	→ Yes
	Vehicle is OK. REPEAT prescribed road test.
	→ No
	Check the customer complaint.

PINPOINT TEST B: MOANING SOUND OF VARIABLE PITCH

STATES	DETAILS/RESULTS/ACTIONS
B1: CHECKING THE AIR FILTER
	1Check the air filter. - Check the air filter, the condition of the air filter supports, the correct installation and tightness of all connections of the intake manifold, exhaust manifold, resonators and all other elements associated with the air intake system.
	• Are all elements in order?
	→ Yes
	Go to B2
	→ No
	REPAIR the faults/defects. REPEAT the prescribed road test.
B2: CHECKING THE EXHAUST SYSTEM
	1Check the exhaust system mounts.
	• Are the exhaust system mounts in order?
	→ Yes
	Go to B3
	→ No
	If necessary, INSTALL new mounts. REPEAT the prescribed road test.
B3: CHECKING THE POWER STEERING
	1Remove the accessory drive belt and listen for a groaning sound.
	• Has the moaning sound been eliminated?
	→ Yes
	MAKE any necessary power steering repairs. Refer to Section 211-02 for additional information.
	→ No
	Go to B4
B4: CHECKING ENGINE/TRANSMISSION MOUNTS IN THE DRIVE AXLE
	1Visually CHECK the condition of the hydraulic mounts of the power unit/gearbox in the block with the drive axle and the presence of leaks in them.
	• Are the powertrain/gearbox mounts in the block with the drive axle in order?
	→ Yes
	Go to B5
	→ No
	Install new mounts if necessary. REPEAT the prescribed road test.
B5: CHECKING THE ALIGNMENT OF THE POWERTRAIN/TRANSMISSION MOUNTS IN THE DRIVE AXLE BLOCK
	1Perform the engine/transaxle mount alignment procedure described in this section.
	• Has the moaning sound been eliminated?
	→ Yes
	Vehicle is OK. REPEAT prescribed road test.
	→ No
	Check the customer complaint.

PINPOINT TEST C: HUMMING/SHAKING/VIBRATION/JERKING AT IDLE

STATES	DETAILS/RESULTS/ACTIONS
C1: CHECKING CABLES/ROPES/HOSES
	1Check the engine compartment for any items that may be hanging between the engine and the body or chassis. Examples include control cables, air conditioning (A/C) hoses, and accelerator cables.
	• Are the elements in order?
	→ Yes
	Go to C2
	→ No
	REPAIR the fault/defect. REPEAT the prescribed road test.
C2: CHECKING THE ENGINE COOLING SYSTEM RADIATOR
	1Check the radiator supports and inserts for secure fastening and their condition. Check the position of the radiator in relation to other elements that may touch it (touching is not allowed).
	• Is the position correct and the inserts OK?
	→ Yes
	Go to C3
	→ No
	REPAIR or INSTALL new components as necessary. REPEAT the prescribed road test.
C3: CHECKING THE EXHAUST SYSTEM
	1Check the exhaust system mounts.
	• Are the exhaust system mounts in order?
	→ Yes
	Go to C4
	→ No
	If necessary, INSTALL new mounts. REPEAT the prescribed road test.
C4: CHECKING POWERTRAIN/TRANSMISSION MOUNTS IN THE DRIVE AXLE BLOCK
	1Visually CHECK the condition of the hydraulic mounts of the power unit/gearbox in the block with the drive axle and the presence of leaks in them.
	• Are the powertrain/gearbox mounts in the block with the drive axle in order?
	→ Yes
	Go to C5
	→ No
	Install new mounts if necessary. REPEAT the prescribed road test.
C5: CHECKING THE ALIGNMENT OF THE POWERTRAIN/TRANSMISSION MOUNTS IN THE DRIVE AXLE BLOCK
	1Perform the powertrain/transaxle mount alignment procedure described in this section.
	• Has the humming/shaking/vibration/jerking been eliminated?
	→ Yes
	Vehicle is OK. REPEAT prescribed road test.
	→ No
	Check the customer complaint.

PINPOINT TEST D: FRONT END VIBRATION

STATES	DETAILS/RESULTS/ACTIONS
D1: TIRE INSPECTION
	1Inspect the wheels and tires. For additional information, refer to Section 204-04.
	• Are the wheels and tires in good condition?
	→ Yes
	Go to D2
	→ No
	If necessary, INSTALL new wheels and tires. Refer to Section 204-04 for additional information. REPEAT the prescribed road test.
D2: INSPECTION AND CHECKING OF WHEEL AND TIRE RUNOUT
	1Inspect and check wheel and tire runout. Refer to Section 204-04 for additional information.
	• Are wheel and tire runout within specifications?
	→ Yes
	Go to D3
	→ No
	MAKE necessary repairs. Refer to Section 204-04 for additional information. REPEAT the prescribed road test.
D3: INSPECTION OF WHEEL BEARINGS
	1Inspect the wheel bearings. Refer to Section 204-00 for additional information.
	• Are the wheel bearings OK?
	→ Yes
	Check the customer complaint.
	→ No
	If necessary, INSTALL new wheel bearings. REPEAT the prescribed road test.

PINPOINT TEST E: NOISE NOT RELATED TO VEHICLE AXLES

STATES	DETAILS/RESULTS/ACTIONS
E1: INSPECTION OF CAR FINISH
	1Check the grille and trim panels to see if they are the source of the noise.
	• Are there any finishing elements that cause noise?
	→ Yes
	INSTALL new trim or REPAIR if necessary.
	→ No
	Go to E3
E2: CHECKING THE HEATING AND VENTILATION SYSTEM FOR NOISE GENERATION
	1Enter the START position.
	2Enter the ON position.
	3Check the heating and ventilation system components for noise generation by turning the heating and ventilation system on and off.
	• Does your heating and ventilation system generate noise?
	→ Yes
	PERFORM diagnostics on the heating and ventilation system. Refer to Section 412-02A / 412-02B for additional information.
	→ No
	Go to E3
E3: CHECKING THE AIR CONDITIONING (A/C) SYSTEM FOR NOISE GENERATION
	1Check the A/C system components for noise generation by turning the A/C system on and off.
	• Is your A/C system making noise?
	→ Yes
	Perform A/C system diagnostics. Refer to Section 412-00 for additional information.
	→ No
	Go to E4
E4: CHECKING NON-FACTORY FITTED ACCESSORIES
	1Check all accessories for noise generation. Example: body and frame contact, antennas, sun visors and fog lights.
	• Do accessories generate noise?
	→ Yes
	Adjust, repair or install new accessories.
	→ No
	Check the customer complaint.

Alignment of powertrain/transmission bearings

NOTE: There is no procedure for alignment of the powertrain/transmission mounts. To visually check the alignment of the powertrain mounts, follow these steps:.

1. Loosen the rear support cushion mounting bolts (if equipped).

2. Loosen the powertrain/gearbox mounting bolts in the block with the drive axle.

3. NOTE: Support the powertrain/transaxle unit at approximate horizontal and vertical alignment.

NOTE: Make sure the right mount and left pad positions match the studs on the powertrain and transaxle to allow the fasteners to be inserted into the large holes in the pad bracket without causing undue stress to the fasteners.

Check the alignment of the powertrain/gearbox supports in the block with the drive axle.

4. Tighten the powertrain/transaxle assembly mounting bolts to the support bracket.

5. Tighten the powertrain/gearbox mount bolts in the block with the drive axle to the body.

6. Tighten the rear support cushion mounting bolts (if equipped).

Noise, Vibration and Harshness (NVH) Diagnostics and Testing