100-04-2 Noise, Vibration and Harshness 100-04-2
DESCRIPTION AND OPERATION
Noise, Vibration and Harshness (NVH)
Noise, vibration and harshness (NVH) is becoming
more important as vehicles become more '
Know the History of the Condition
sophisticated and passenger comfort levels
increase. This section is designed to aid in the
- Did it start suddenly or appear gradually?
diagnosis and testing and repair of NVH concerns.
- Was it related to some other occurrence such
- Noise is defined as sounds not associated with
as a collision or previous part replacement?
the operation of passenger compartment
- Know how the condition made itself known; it
equipment that interface with customer
may be an important clue to the cause.
satisfaction.
- Vibration is defined as impulses felt by the
customer that are not caused by road surface Know the Probability of Certain
changes. Conditions Develop~ng
- Harshness is a ride quality issue where the - Look for the simple rather than the complex.
customer feels that the vehicle response to the
road surface is sharply transmitted to the
- For example:
customer.
- Electrical conditions usually occur at
connections rather than components.
Diagnostic Theory - An engine no-start is more likely to be caused
by a loose wire or small adjustment rather
than a sheared-off
camshafi. Diagnosis is more than just following a series of
interrelated steps in order to find the solution to the - Know the difference between impossible and
specific condition. It is a way of looking at systems improbable. Certain failures
in a system can be
that are not functioning the way they should and improbable
but still happen.
finding out why. Also it is knowing how the system
- New parts are just that, new. It does not mean
should work and whether it is working correctly. they are always
good functioning parts.
There are basic rules for diagnosis. If these rules
are followed, the cause of the condition is usually
Do Not Cure the Symptom and Leave
found the first time through the system. the Cause
Know the System
- Know how the parts go together. Lowering
the pressure in a front tire may correct
the condition of a vehicle leaning to one side, but
it does not correct the original condition.
- Know how the system operates as well as its
limits and what happens when the system goes
Be Positive the Cause is Found
wrong.
- Sometimes this means checking the system - Double check findings.
against one that is known to be working
- What caused a worn component?
correctly.
- A loose transmission or engine mount could
indicate that other mounts are also loose.
Know the History of the System
Diagnostic Charts
A clue in any one of these areas may save time:
- How old or new is the system? Charts are a simple
way of expressing the
relationship between basic logic and a physical
- What kind of treatment has it had?
system of components. They help discover the ,.
- Has it been serviced in the past in such a
cause of a condition in the least time. Diagnostic (,-
manner that might relate to the present
charts combine many areas of diagnosis into one
condition? visual display:
- What is the service history?
2006.0 Fiesta 12/2006 G28448en
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100-04-6 Noise, Vibration and Harshness 100-04-6
DIAGNOSIS AND TESTING
2. AccelerationIDeceleration: With slow
acceleration and deceleration, a shake is
sometimes noticed in the steering
wheellcolumn,
seats, front floor panel, front door trim panel or
front end sheet metal. It is a low frequency
vibration (around
9-1 5 cycles per second). It
may or may not be increased by applying the
brakes lightly. REFER to
Idle
BoomIShakeNibration in the Driveline Noise
and Vibration Symptom Chart.
High Speed: A vibration is felt in the front floor
panel or seats with no visible shake, but with
an accompanying sound or rumble, buzz, hum,
drone or booming noise. Coast with the clutch
pedal depressed (manual transmission) or shift
control selector lever in "N" (NEUTRAL)
(automatic transmission) and engine idling. If
vibration is still evident, it may be related to
wheels, tires, front brake discs, wheel hubs or
front wheel bearings. REFER to Shake and
Vibration While Driving in the Driveline Noise
and Vibration Symptom Chart.
4. Engine rpm Sensitive: A vibration is felt
whenever the engine reaches a particular rpm.
It will disappear in neutral coasts. The vibration
can be duplicated by operating the engine at
the problem rpm while the vehicle is stationary.
It can be caused by any component, from the
accessory drive belt to the clutch or torque
converter which turns at engine speed when the
vehicle is stopped. REFER to Shake and
Vibration While Driving in the Driveline Noise
and Vibration Symptom Chart.
5. Noise and Vibration While Turning: Clicking,
popping or grinding noises may be due to the
following:
worn, damaged or incorrectly installed front
wheel bearing.
damaged
powertrainldrivetrain mounts.
Road Conditions
An experienced technician will always establish a
route that will be used for all NVH diagnosis road
tests. The road selected should be reasonably
smooth, level and free of undulations (unless a
particular condition needs to be identified). A
smooth asphalt road that allows driving over a
range of speeds is best. Gravel or bumpy roads
are unsuitable because of the additional road noise produced.
Once the route is established and
consistently used, the road noise variable is
eliminated from the test results.
N0TE:Some concerns may be apparent only on
smooth asphalt roads.
If a customer complains of a noise or vibration on
a particular road and only on a particular road, the
source of the concern may be the road surface. If
possible, try to test the vehicle on the same type
of road.
Vehicle Preparation
Carry out a thorough visual inspection of the
vehicle before carrying out the road test. Note
anything which is unusual. Do not repair or adjust
any condition until the road test is carried out,
unless the vehicle is inoperative or the condition
could pose a hazard to the technician. After
verifying that the condition has been corrected,
make sure all components removed have been
installed.
Power Steering Conditions
c !
Check for the noise in the following conditions to
verify the customer concern.
Check for the noise in several temperature
conditions.
Is the noise from when the vehicle was new?
Can the noise be repeated constantly or is it
random?
Check the condition of the vehicle age, mileage
and service record.
Interview the customer to find the operating
condition in which the noise will occur. Test the
vehicle based on the
detail(s) from the customer
interview.
Follow the power steering operation noise
condition tables below, to find which condition
the noise will occur.
Power Steering Operation Noise Check
Step 1 : Check for NVH concerns from non-steering
components, which may sound like noises coming
from the steering system.
I:. ':
2006.0 Fiesta 121zoo6 G37349en
procarmanuals.com
205-04-3 Front Drive Halfshafts 205-04-3
DESCRIPTION AND OPERATION
Front Drive Halfshafts
Drives hafts
Conventional driveshafts are used on the front axle.
For servicing purposes it is important to note that
the inner tripod joints are pressed onto the shaft.
This has made it possible to reduce noise levels
when the vehicle is pulling away from standing.
The outer joint has not been approved for service
repairs, so in the event of a fault it is necessary to
replace the complete shaft and outer joint
assembly. The inner joints are dismantled with the
aid of a puller. The driveshaft needs to be removed
first.
In order to install a new boot on the outer joint, it
is first necessary to remove the driveshaft and then
disassemble the inner joint. A special service kit is
available in service for this purpose, consisting of
the inner and outer boot and the necessary small
parts.
The same amount of grease is used to pack the
inner and outer joints.
- The PAC nut used for securing the driveshaft to ' the wheel hub must not be reused.
Item Description
I 1 I Securing clip for bearings I
Heat shield (only for vehicles with a petrol
1 * 1 engine)
It should also be noted that vehicles with a petrol
engine have an additional heat shield on the bearing of the intermediate shaft of the right-hand
driveshaft. This is required to prevent the grease
in the bearing from overheating as a result of the
closeness to the catalytic converter.
2006.0 Fiesta 1212006 G202088en
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Brake System - General Information
DIAGNOSIS AND TESTING
evidence of a brake concern. Check for the brake
warning indicator illumination and the fluid level in
the master cylinder reservoir.
Normal Conditions
The following conditions are considered normal
and are not indications that the brake master
cylinder is in need of service.
- Modern brake systems are not designed to
produce as hard a pedal effort as in the past.
Complaints of light pedal efforts should be
compared to pedal efforts of another vehicle, of
the same model and year.
- During normal operation of the brake the fluid
level in the reservoir will rise during brake
application and fall during release. The net fluid
level
(i.e., after brake application and release)
will remain unchanged.
- A trace of brake fluid will exists on the brake
booster shell below the master cylinder
mounting flange. This results from the normal
lubricating action of the master cylinder bore
end seal.
- The fluid level will fall with brake shoe and lining
wear.
Abnormal Conditions
N0TE:Prior to performing any diagnosis, make
sure the brake system warning indicator is
functional.
Changes in brake pedal feel or travel are indicators
that something could be wrong with the braking system. The diagnostic procedure and techniques
use brake pedal feel, warning indicator illumination
and low brake fluid level as indicators in diagnosing
braking system concerns. The following conditions
are considered abnormal and indicate that the
brake master cylinder is in need of service.
- The brake pedal effort is excessive. This may
be caused by a bind or obstruction in the pedal
.
or linkage, clogged fluid control valve or ( ' insufficient booster vacuum.
- The rear brakes lock up during light pedal force.
This may be caused by incorrect tire pressures,
grease or fluid on the brake shoes and linings,
damaged brake shoes and linings, incorrectly
adjusted parking brake, or damaged or
contaminated brake pressure control valves.
- The brake pedal effort is erratic. This condition
could be caused by a brake booster malfunction,
extreme caliper piston knock back or incorrectly
installed brake shoes and linings.
- The brake warning indicator is ON. This may
be caused by low fluid level, ignition wire routing
too close to the fluid level indicator assembly,
or float assembly damage.
Bypass Condition Test
1. Check the fluid in brake master cylinder. Fill the
brake master cylinder reservoir if low or empty.
2. Observe the fluid level in the brake master
cylinder reservoir. If after several brake
applications, the fluid level remains the same,
measure the wheel turning torque required to
rotate the wheels with the brakes applied as
follows:
Place the transaxle in NEUTRAL and raise and
support the vehicle. REFER to: (1 00-02 Jacking
and Lifting)
Jacking (Description and Operation),
Lifting (Description and Operation).
Apply the brakes with a minimum of 445 N (100
Ib) and hold for approximately 15 seconds. With
the brakes still applied, exert a torque on the front
wheels of 10.1 Nm (75
1b.R). If either wheel rotates,
install a new brake master cylinder. REFER to:
(206-06 Hydraulic Brake Actuation)
- The brake pedal goes down fast. This could be Brake Master Cylinder - RHD (Removal and
caused by an external or internal leak. Installation),
- The brake
pedal eases down slowly. This could Brake Master Cylinder - LHD
(Removal and
be caused by an external or internal leak. Installation).
- The
brake pedal is low and or feels spongy. This
condition may be caused by no fluid in the brake
Non-Pressure Leaks master cylinder reservoir, reservoir cap vent
holes clogged or air in the hydraulic system.
Any empty brake master cylinder reservoir
condition may be caused by two types of
non-pressure external leaks.
2006.0 Fiesta 1212006
procarmanuals.com
206-00-31 Brake System - General Information 206-00-31
DIAGNOSIS AND TESTING
Type 1: An external leak may occur at the master
cylinder reservoir cap because of incorrect
( positioning of the gasket and cap. Reposition the
cap and gasket.
Type
2: An external leak may occur at the reservoir
mounting seals. Service such a leak by installing
new seals.
2006.0 Fiesta 1212006 G28494en
procarmanuals.com
206-0716 Power Brake Actuation 206-0716
DESCRIPTION AND OPERATION
Release of the brake assistant
Item Description
I I I ~ock sleeve I
1 3 IVacuum cylinder I
To release EBA, the brake pedal must be fully
released,
i.e. it must be returned to its rest position.
When this occurs, the control housing together with
the valve piston move back into the rest position.
The key is pressed against the stop on the vacuum
cylinder and by this the lock sleeve is slid back into
its rest position.
The balls can again be moved outward by the ball
sleeve, and the ball cage is again free to move
axially and the balls free to move radially.
Service
It is not possible to repair the EBA. A new brake
servo unit must be installed.
2006.0 Fiesta 12/2006 GI 63289en
procarmanuals.com
206-09A-6 Anti-Lock Control 206-09A-6
DESCRIPTION AND OPERATION
Wheel speed sensors
I f
The wheel speed sensors are active sensors. They
are supplied with a voltage from the ABS control
unit after the ignition is switched on.
Item Description The ABS control unit can be diagnosed via the
The pulses are picked up from a mechanically
encoded ring, which is built into the wheel bearings
on the front wheels while for the rear wheels it is
a metal ring which is mounted on the stub axle.
The registered wheel speed is converted into a
digital (square-wave) signal by the electronics
integrated in the sensor and is then transmitted to
the ABS control unit. Data Link Connector
(DLC).
The hydraulic unit is pre-filled for service.
1
2
Data transmissions to the ABS control unit take
place via a 2-stranded connecting cable.
NOTE: The wheel speed sensors must not be
checked for voltage with an ohmmeter.
Sensor
Installation position.
It also supplies the vehicle speed signal, which is
calculated from the wheel speed sensor signals.
This is transmitted via the CAN bus to the
Powertrain Control Module (PCM)
2006.0 Fiesta 1212006 GI 63291 en
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21 1-00-1 6 Steering System - General Information 21 I -00-1 6
DIAGNOSIS AND TESTING
8m ACAUTION:T~ prevent damage to the
steering linkage, turn the steering wheel to
move the steering linkage to the steering
lock stop.
Turn the steering wheel to position the steering
linkage against the left-hand steering lock stop.
9. N0TE:To isolate the steering gear design
'clearance, check the left-hand
tiemrod with
the steering held against the left-hand
steering lock stop.
With the aid of another technician holding the
steering against the left-hand steering lock stop,
firmly grasp the left-hand road wheel and apply
a rocking motion to check for any free play in
the tie-rod.
IQ Detach the steering gear boot from the steering
gear body and check for free play at the tie-rod
inner ball joint.
11. If there is free play at the tie-rod inner ball joint,
install a new tie-rod.
REFER to: Tie Rod (211-03 Steering Linkage,
Removal and lnstallation).
I2 If there is free play at the tie-rod end, install a
new tie-rod end.
REFER to: Tie Rod End (21 1-03 Steering
Linkage, Removal and lnstallation).
Turning Effort Test
N0TE:Before carrying out this test, make sure that
the suspension components are serviceable.
N0TE:Before carrying out this test, make sure that
the steering column is serviceable.
N0TE:Before carrying out this test, make sure that
the front toe adjustment and tire pressures are
correct. 1.
Park the vehicle on a dry, even surface and
apply the parking brake.
/- ,
2. Remove the driver air bag module.
REFER to: Driver Air Bag Module (501 -20
Supplemental Restraint System, Removal and
Installation).
3. Remove the driver air bag module wiring
harness from the driver air bag module.
REFER to: Driver Air Bag Module Wiring
Harness (501 -20 Supplemental Restraint
System, Removal and Installation).
4. Connect the driver air bag module wiring
harness to the clockspring.
5. Connect the air bag simulators to the driver air
bag module wiring harness in place of the driver
air bag module at the top of the steering column.
6. Start the engine and turn the steering wheel
from lock to lock several times until the power
steering fluid has reached normal operating
temperature.
7. Using a suitable torque wrench and socket,
check the steering wheel turning effort.
8. If the steering wheel turning effort is greater than
the specification, install a new power steering -
pump. REFER to: i
Specifications (21 1-00 Steering System -
General Information, Specifications),
Power Steering Pump
- I .3L Duratec-8V
(Rocam) (21 1-02 Power Steering, Removal
and lnstallation),
Power Steering Pump
- 1.25L Duratec-1 6V
(Sigma)/l.4L Duratec-1 6V (Sigma)/l .6L
Duratec-l6V (Sigma), Vehicles With: Air
Conditioning (21 1-02 Power Steering,
Removal and lnstallation),
Power Steering Pump
- I .25L Duratec-I 6V
(Sigma)/l.4L Duratec-1 6V (Sigma)/l .6L
Duratec-I 6V (Sigma), Vehicles Without: Air
Conditioning (21 1-02 Power Steering, Removal and lnstallation),
Power Steering Pump
- 1.4L Duratorq-TDCi
(DV) Diesel (21 1-02 Power Steering, Removal
and lnstallation),
Power Steering Pump
- 2.OL Duratec-HE (M14)
(21 1-02 Power Steering, Removal and
Installation).
Disconnect the air bag simulators from the driver
air bag module wiring harness.
//
IQ Disconnect the driver air bag module wiring i,,.
harness from the clockspring.
2006.0 Fiesta 1212006 GI 49906en
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